Stun, Daze and similar stuff don't impede your movement...
...they make your mind funny.
While you are stunned, there's nothing holding your body to move. You just can't think right to actually do something. If you take a really hard blow to your head, that won't make your body harder to move - it will make your brain go gonzo for a few secs, before you became aware of what's really happening.
Stun is not about movement, is about senses of what's going on.
Freedom of Movement makes "your body work right", not anything else. It allows you to move, but not allows you to think. You can't think if you're dead. Or Stunned.
Paralysis don't block purely mental actions, so it don't block "thinking".
Slow makes your body... well, slower, but it doesn't affect your thinking.
Web is... well, a web. It hinders your body, not your mind.
Stun, Daze, Dazzle and similar stuff, on the other hand, makes your senses go wacko, so they aren't really blocking your movement. Stun never stopped you from moving, it just stopped you from thinking for a while - and since you don't think, you don't act.
So, the point is,
If something affect your senses, Freedom of Movement can't help you.
Think like a "Houdini Effect". Houdini can escape from almost anything, considering that he
knows what's going on. If you throw him with a concussion inside a closed coffin... well... he will stay there.
So, to determine what Freedom of Movement removes or not, use a simple rule:
Why I can't move?
If you can't move because a spell or something is hindering your body to move, like Web, Freedom of Movement can help you.
If you can't move because a spell or something is making your brain go gonzo, like Stun, or because your body becomes something that can't normally move, like stone from Flesh to Stone*, it won't help you.
*Flesh to Stone don't impede your movement, it merely limits you to the movement that a stone statue is allowed to do. A "Freedom of Movement"-ed and "Web"-ed person would become a completely untangled stone statue.
Also, read Freedom, the 9th level spell:
The subject is freed from spells and effects that restrict its movement, including binding, entangle, grappling, imprisonment, maze, paralysis, petrification, pinning, sleep, slow, stunning, temporal stasis, and web. To free a creature from imprisonment or maze, you must know its name and background, and you must cast this spell at the spot where it was entombed or banished into the maze.
Emphasis mine.
Freedom removes a bunch of effects, like Flesh to Stone and Stun. It would seem rather... strange to say that a way lower-level spell can do almost all the things that a 9th level spell can. Freedom is Freedom, not Freedom of Movement.
Rules as written: No limit
Armors limit your Dex bonus to AC. Deepwardens do not have Dex bonuses to AC, they have Con bonuses to AC. The Con bonus replaces the Dex bonus (and so you would not get it in situations where you lose your Dex bonus to AC), but it still is not a Dex bonus and thus the limits of the armor do not apply. And, indeed, there’s no reason why an armor’s weight or inflexibility would prevent you from benefiting from your resilience and connection to the earth.
Intent: Unknown, and unknowable
As far as what the authors intended, that’s anyone’s guess. The author never wrote anything on the subject aside from the original publication, so we have no evidence one way or the other.
Precedent: No limit
As for precedence, generally speaking the special rules for one ability score do not apply when you swap to another ability score. There are instances where you can replace your Strength to damage with Dexterity to damage, but RAW you do not get ½Dexterity to damage on a light weapon or 1½Dexterity to damage on a weapon wielded two-handed, unless it explicitly says so. (Dragon vol. 221 has the Corsair which explicitly halves Dexterity to damage with light weapons, for example)
FAQ: Limit
However, there is an FAQ entry on the question. The FAQ, it must be very clearly stated, is not errata. It is supposed to only explain the rules that already exist. If its statements contradict the actual rules, officially, the actual rules take precedence every single time. And the FAQ has been wrong many times, in many cases quite blatantly so. Finally, the FAQ is not (usually) written by the original authors of the book, so it does not correspond to the author’s intent, either.
All together, the FAQ is worth very little, and has a very poor reputation. In fact, it’s so bad that when this poster in the thread Squera linked learned that the FAQ said the Con bonus was limited, it proved to him that it actually wasn’t!
At any rate, the FAQ has this to say:
Does the deepwarden’s Stone Warden ability (RS 105) still have a maximum Dexterity bonus to his Armor Class, and does that maximum still apply to his Constitution?
The maximum Dexterity bonus should be treated as the maximum ability bonus given by the armor, so if you were playing a deepwarden wearing full plate, you would only add 1 to your Armor Class from your Constitution.
Conclusion: Rule it based on what improves your game most
Personally, I think it makes almost no sense that restrictive armor would inhibit a Con bonus to AC, I think that deepwardens make sense in heavy armor and shouldn’t be penalized for wearing it, and I don’t think the deepwarden or the AC they can get is overpowered or problematic, so I would not limit it. You may answer any or all of those questions differently. Ultimately, remember than AC is a limited thing, and lots of nasty things ignore AC; having a lot of it only does so much for you.
If you would like a compromise, here’s a suggestion. Purely houserule with no basis in the rules, either deepwarden’s or elsewhere in precedence, but it might be a good solution:
The deepwarden’s Constitution bonus to AC is limited by her armor’s maximum Dexterity bonus, just as the Dexterity bonus it replaces would be. However, the Constitution bonus is not limited for the purposes of AC against touch attacks. For example, if a deepwarden with 18 Constitution (+4) wears Chainmail (+5 AC, +2 maximum Dexterity bonus), and has no other bonuses to AC, his AC is 17 (+5 armor, +2 Consitution), but his touch AC is 14 (+4 Constitution). A deepwarden’s touch AC may not exceed her regular AC.
I don’t think this is necessary, but it does prevent the high-end AC that you might get from armor+Con, while still giving a deepwarden a good bonus for their class feature.
Remember, a class feature is supposed to make you better. Yes, Con, not limited by max Dex, is better than what the deepwarden had before, but that isn’t necessarily a problem. It’s only a problem if it’s “too much better,” and I really don’t think it is.
Best Answer
As written, contingency triggers as soon as its condition is true, not as soon as the caster is aware that it is true. Neither caster’s senses, nor anyone else’s senses, are involved: it just happens. The spell changes the fundamental laws of the universe such that the next time X happens, spell Y is cast.
So the question isn’t about who knows, it’s about what is fact. Going down the list:
Contingency certainly seems to be capable of responding to certain times (time of day, time since an event); the tricky part here is establishing the condition clearly. Many settings don’t have rigorously-defined times, so it’s not clear that “6 PM” is going to mean anything in-character. On a globe, time zone issues can also be problems. But something like “noon at Town” seems likely to work.
The open-ended nature of the spell leaves that conceivable, but I’d go with “no,” largely on the basis that personal thoughts are not “facts of the universe” and detecting another’s thoughts requires a Saving Throw. Contingency does not have a built-in read thoughts.
Similar to how I feel about reading minds: predicting the future requires special, powerful, and uncertain magic. The future is not a fact, not yet, and so contingency cannot be triggered by it.
If the disguise included some form of hiding from magic (nondetection), then no, but a simple mundane disguise would not affect contingency.
Magic can detect alignment without giving the subject a Saving Throw. Somehow, alignment is an objective observable reality. So things like “a creature of Evil alignment” and an “Evil action” could probably be valid. Whether or not alignment is the same as morality is debatable and beyond the scope of this question.
Contingency doesn’t “sense” per se; it just automatically reacts to facts. So, basically, the subject’s lack of a particular sense doesn’t come into play.
Same deal as thoughts; probably not.
Same as 6; it doesn’t “hear” or “see” but can certainly react to facts that the subject cannot hear or see.
Yes.
The subject doesn’t come into play; it’s more about what “magic” could have the information. Protected information (e.g. stuff magic would require a failed Saving Throw to get) I’ll call unavailable, but even that might be wishful thinking on my part.
In short, contingency is horribly-broken as written. You can try to rein it in by houseruling in some limitations, but I’m not convinced they’ll be enough. The spell is almost-certainly the most powerful that Wizards ever wrote.
As for the timing of simultaneous events, the rules don’t really handle that well. Presumably you could just use whoever’s player declared the action first, but in the case of purely-reactive contingencies, both could be triggered by the same fact and therefore be “simultaneous.” For creatures’ actions, I’d consider houseruling an expansion of Initiative to use opposed Initiative checks in such cases. But contingency is not a creature and once cast, it doesn’t have anything to do with the creature it’s been cast on until it triggers a spell on that character. I think perhaps the best solution is to use opposed Caster Level checks?