Response to your Incarnum-related thoughts.

It could work, but it won’t be easy

Incarnum is a fairly obvious system to use and a good idea.

But you would have to work out Essentia, Bind, and Chakra progressions, and figure out a Soulmeld list. The Incarnate’s list is mostly for skill-monkeying, but most of your eventual list will probably come from it. The Soulborn list has one gem (Thunderstep Boots) but mostly overlaps with the Incarnate. The Totemist list is probably not overly relevant as most of it is themed on natural attacks, which won’t work in conjunction with the Mind Blade very well.

Essentia, Bind, and Chakra progressions will probably be based on the Incarnate or Totemist, probably with some slight downward tweaking. Weapons usually use the Hands chakra, which usually comes later, so that will be awkward. Don’t base anything on the Soulborn as it is atrocious.

Worth noting: the Incandescent Champion and Ironsoul Forgemaster prestige classes both have similar themes. The Incandescent Champion is pretty poor, and the Ironsoul Forgemaster is dwarf-only. Still, you might be able to steal ideas.

This solution is similar to a fairly popular one I’ve seen, but don’t like

Some have suggested that a solution to the weaknesses of both Soulknife and Soulborn is to simply combine the two classes à la the Gestalt rules from Unearthed Arcana in a non-Gestalt game (or treat them as one side in a Gestalt game). This shores up a lot of numbers, which is nice, but ultimately neither class has much going for it.

Basically, taking a bunch of near-useless class features and adding in another group of near-useless class features just means you have more near-useless class features; at no point to actually inject something really useful. The Soulborn//Soulknife still has a magic sword (yawn), the craptastic Psychic Strike, and Meldshaping them comes online absurdly late and remains extremely limited throughout the class’s career. I’m neither impressed nor convinced that this combination actually solves anything.

Your ability scores don’t really match your character description. You have little-to-no use for that Strength, that I can tell, and it sounds like your Charisma really ought to get an 18, since you’re staying on the back lines and focusing on song and spell.

Also, please consider my general recommendations for the bard class, as I’m going to avoid repeating myself.

And immediately breaking my claim that I’d not repeat myself: you don’t list Dragonfire Inspiration. You should; it is one of the absolute best feats for a buffer-bard, and is a very good reason to make your human character specifically a silverbrow human. Both Dragonfire Inspiration and silverbrow human are found in Dragon Magic.

Feats You List

Obtain Familiar/Improved Familiar

Decent, but you have to pay attention to your familiar, i.e. remember it’s there, maintain its stat-sheet, and so on. And then there’s the risk of it blowing up in your face and costing you a bunch of XP. Can be quite good, but I’d generally pass.

Song of the Heart

Very good, remember that you can get it as a bonus feat at Bard 3 instead of Inspire Competence. This is generally seen as a good trade, though Inspire Competence is OK enough that it can be worth it to take Song of the Heart as a feat so you get both.

Haunting Melody

By the time you can take it (6th), you’re starting to be really worried about the “mind-affecting, fear effect” aspect of the feat. The effect is decent, but not amazing at the levels it’s available, and it will become dead weight at high levels.

Lingering Song

In my experience, combat rarely lasts long enough for this to matter. The feat does nothing until, at the earliest, round 7, and most fights don’t last that long. I would pass.

Melodic Casting

The ability to cast while performing is eh for much the same reasons as Lingering Song. It’s better than Lingering Song, but ultimately it’s not much more likely to come up.

But that isn’t why you take the feat: you take the feat to replace Concentration with Perform. That is amazing for any bard, an ASAP pick up for almost all of them.

Versatile Spellcaster

It’s definitely not bad, but ultimately bards aren’t the best option for it. You just have fewer spells per day. Definitely don’t bother until high levels.

Lyric Spell

Meh? Ultimately, you almost-certainly will end up with way more daily uses of bardic music than you know what to do with, and this is a good way to burn through those – but you’ll burn through them fast. I like it better than Versatile Spellcaster, though, and would not take both.

Ironskin Chant

By 9th level, 5 damage is just... not a lot. If someone is surrounded by a bunch of low-damage, many-attacks enemies, then it can be golden, but a feat is a lot to spend on that possibility. Better for people to just, ya know, avoid getting surrounded. If it were immediate, you could argue it’s awesome for sudden ambushes, but as a swift you need to see the situation coming.

On the other hand, you do have a lot of uses of bardic music available after a while, and swift actions can be cheap. There are better options but it’s not bad.

Doomspeak

If this is worthwhile for a 6th-level character (and I’m not sure it is), it’s definitely not worth your 15th-level feat. You could spend another feat to get Intimidate in-class, but that’s way too much work for this. Pass.

Metamagic Song

Metamagic cost-reducers are one of the tried-and-true ways to true power in 3.5. This has far more sensible restrictions than Divine Metamagic, so I won’t call it out as definitively overpowered, but it is really strong.

The other issue is that the bard doesn’t really have the clear-and-obvious choices for metamagic that other classes do, and doesn’t get any as bonus feats. You have very limited feats to use for this.

Warning Shout

Reflex saves are the least-important of the three, but this is a pretty sizeable bonus, as an immediate action, and the cost to use it is not unreasonable. I’d definitely consider it.

Combat Panache

I love the name of this feat. And every time I read it, it disappoints me. Don’t bother.

Dragonsong

You really want to try to avoid mind-affecting effects if you can; too many things are immune. This bonus is small and niche. Pass.

Snowflake Wardance

This is a great feat, but if you’re not melee-focused, then it serves no purpose. Your ability scores are not exactly ideal, either, though the fact that you will be getting the largest cloak of charisma you can, and at high levels probably using wish or tomes for Charisma, mean the difference is going to wind up much higher than +2.

Sound of Silence

Deafening is not that bad a condition; the cost to inflict it here is just too high.

Point Blank Shot

Pure tax, plain and simple, and a bad one. The only reason to ever take this is just so you can take the actually-good things that require it, and you don’t need those that I can tell.

Precise Shot

If you are looking to use a lot of rays (not really a bard thing but you could), consider the rod of magical precision that allows you to buy Precise Shot for cheap. It’s in Complete Mage.

Aside from that, you only break out a bow when the battle is won and you’re taking potshots to pick people off. Don’t burn feats on that.

Battle Dancer

Tiny bonus is tiny. This is not worth a feat.

Disguise Spell

Here I disagree; Disguise Spell is awesome. And on a cowardly character? Perfect. Strongly recommend this.

Extra Music

You are going to have approximately 20 uses of bardic music in a day; for most purposes, Extra Song is pointless because you were never going to use all 20 in the first place. At low levels, it’s much better, though.

If you do go in for a lot of alternate uses of bardic music, particularly Lyric Spell and/or Metamagic Song, it becomes much more valid, but I still probably wouldn’t bother.

Extend Spell

Solid enough metamagic, reasonably priced. Good feat.

Sculpt Spell

Note that Sculpt Spell is not the same as the archmage’s Mastery of Shaping, nor does it make a spell (S) sculptable – it just switches area spells into other standard shapes (a cylinder, cone, ball, line, or series of cubes). This makes it rather difficult to use since you won’t be able to just pick and choose your targets, you still have to make it fit inside this shape. At +1 spell level, I’d much rather just cast a higher-level spell. Even with Metamagic Song, you couldn’t apply it to your best spells.

Other Feats

Chain Spell

This is an awesome feat for a buffer, allowing you to hit multiple people with usually-single-target buffs.

Charming the Arrow

If you are actually going to go in for that archery stuff, and can somehow finagle the Fey requirement, Charming the Arrow would be obviously-awesome for you.

Deceptive Spell

Fantastic opportunity for shenanigans, even more than Disguise Spell, but it costs a spell level.

Dragonfire Inspiration

Mentioned, mentioning it again. The feat is fantastic.

Enlarge Spell

is an awful feat you will most likely never use. That said, it is required for the excellent war weaver prestige class from Heroes of Battle – worth considering.

Invisible Spell

Possibly even more capable of shenanigans than is Disguise Spell.

Rapid Metamagic

This eliminates the casting-time increase of metamagic feats for spontaneous casting. If you are going to be using a lot of metamagic, you need this feat ASAP.

Unfortunately, taking it is another metamagic feat you aren’t taking. If you take this and Metamagic Song to enable metamagic, but only have one or two situational metamagic feats (like Extend and Sculpt), those two feats enabling metamagic are kind of wasted.

Reach Spell

Turn a touch-attack spell into a ranged spell, which can be very useful in conjunction with Chain Spell.

Song of the White Raven

You are not melee-focused, which makes this Tome of Battle feat seem odd at first, but there are more than sufficient opportunities to make this worthwhile. A single level of crusader gets you some excellent party-buffing options, like leading the charge and white raven tactics.¹ Martial spirit and crusader’s strike or revitalizing strike also allow you to potentially heal allies if you ever do get in melee (or at least, use that whip), which seems appropriate.

But most of all, it allows you to take Song of the White Raven, which allows you to start your Inspire Courage as a swift action. That is a huge deal, and totally worth a level and a feat.

1. ^{Tome of Battle is, by far, the best-designed, best-balanced book in 3.5, but even the best books have problems. For Tome of Battle, the most notorious problems are iron heart surge and white raven tactics, but both are fine when used reasonably. For white raven tactics, simply disallow using it on yourself (as was likely originally intended), and it becomes strong, but not broken. For iron heart surge, should it come up, I like to just replace the entire text of the feat with BY CROM!! and then it seems to play fine.}

Spellbreaker Song

Not a feat, but rather an alternate class feature replacing Countersong (which is absolutely useless), this allows you to disrupt other spellcasters. A good deal.

Talfirian Song

I don’t actually recommend this feat, but it should be mentioned. Combined with Metamagic Song, Talfirian Song allows bardzilla, very similar to a cleric’s use of Divine Metamagic. Even though it takes three feats instead of one, and is limited by the bard’s spell list, this is still overpowered for many games, particularly one described as low-power.

Recommendation

Assuming silverbrow human,

• 1st level
  • Invisible Spell
  • Dragonfire Inspiration (Human bonus feat)
• 3rd level
  • Reach Spell
  • Song of the Heart (Music of Creation bonus feat)
• 6th level
  • Metamagic Song
• 9th level
  • Rapid Metamagic
• 12th level
  • Chain Spell
• 15th level
  • Disguise Spell
• 18th level
  • Extend Spell