The first option

The Soulknife can make attacks out to 60 feet and no further. These attacks are made with a straight d20 roll (absent some other situational factor).

Normal range is the range at which attacks are made with a straight d20 roll. Long range is the range beyond normal range that attacks may still be made but at disadvantage. The Soulknife's ranged psychic blade attacks do not have this latter distance.

In essence, what is happening is the Soulknife's attacks are treated like a spell attack (which do not feature a long range, either the target is within range or it isn't) except that it isn't a spell attack. It is a conventional ranged attack that does psychic damage.

The Soulknife rogue checks to see if a target is within 60 feet. If so, it may roll a d20 to attack. If the target is outside of 60 feet, no attack may be made.

The reason the wording for the feature is a bit verbose is that the attack works in a unique way but which still fits within the conventions for attacks in fifth edition.

Is there any way at all in pathfinder to wield a weapon that is actually huge, not effectively huge but actually huge in size?

Yes

But it very much depends on what kind of weapon you want to wield and which size you are.

First, the Rules for Inappropriately Sized Weapons state:

A creature can’t make optimum use of a weapon that isn’t properly sized for it. A cumulative –2 penalty applies on attack rolls for each size category of difference between the size of its intended wielder and the size of its actual wielder. If the creature isn’t proficient with the weapon, a –4 nonproficiency penalty also applies.

The measure of how much effort it takes to use a weapon (whether the weapon is designated as a light, one-handed, or two-handed weapon for a particular wielder) is altered by one step for each size category of difference between the wielder’s size and the size of the creature for which the weapon was designed. For example, a Small creature would wield a Medium one-handed weapon as a two-handed weapon. If a weapon’s designation would be changed to something other than light, one-handed, or two-handed by this alteration, the creature can’t wield the weapon at all.

Examples for a Medium character:

• He can wield a large one-handed weapon as a two-handed weapon. [1 size difference: one-handed → two-handed]
• He can wield a large light weapon as a one-handed weapon. [1 size difference: light → one-handed]
• He can wield a huge light weapon as a two-handed weapon. [2 size differences: light → one-handed → two-handed]

Examples for a Small character:

• He can wield a medium one-handed weapon as a two-handed weapon. [1 size difference: one-handed → two-handed]
• He can wield a medium light weapon as a one-handed weapon. [1 size difference: light → one-handed]
• He can wield a large light weapon as a two-handed weapon. [2 size differences: light → one-handed → two-handed]

The Titan Fighter fighter archetype & the Titan Mauler barbarian archetype have two (very similar) abilities – Giant Weapon Wielder & Massive Weapons respectively – that allow you to use two-handed weapons one size larger than you as two-handed weapons. That's all these two abilities do. The reason they don't stack with any of the other abilities is this main limit:

• The weapon has to be intended for a creature 1 size difference larger than you.

This means that no matter what you do, this ability can never affect any weapons made for creatures 2 size differences larger than you. So a Medium creature can never use this ability in any way to use a Huge weapon, and a Small creature can never use this ability in any way to use a Large weapon.

The only reasonable way to use this ability on such weapons is to change your own size – actually [i.e. you really grew to a larger size] or effectively [i.e. you are treated as if you had grown to a larger size].

There are numerous ways to change your size actually, for example the spell Enlarge Person, which would grow a Medium creature to a Large one, or a Small creature to a Medium one. Since you said Mythic rules are available to you, Mythic Enlarge Person can grow you two size categories, e.g. a Medium to a Huge creature or a Small to a Large creature; both spells can be made permanent with Permanency.

In order to change your size effectively, you need an ability that makes you count as one size category larger than you actually are for the purpose of wielding weapons. Since I am not aware of any such (non-third-party) ability at the moment, I'll take the Powerful Build racial trait you mentioned as an example and then rewrite the relevant part so that it would stack with the Titan Fighter/Mauler's ability:

The physical stature of half-giants lets them function in many ways as if they were one size category larger. Whenever a half-giant is subject to a size modifier or special size modifier for a Combat Maneuver Bonus or Combat Maneuver Defense (such as during grapple checks, bull rush attempts, and trip attempts), the half-giant is treated as one size larger if doing so is advantageous to him. A half-giant is also considered to be one size larger when determining whether a creature’s special attacks based on size (such as grab or swallow whole) can affect him. A half-giant can use weapons designed for a creature one size larger without penalty. A half-giant is also considered to be one size larger when determining which weapons are appropriately sized for him. However, his space and reach remain those of a creature of his actual size. The benefits of this racial trait stack with the effects of powers, abilities, and spells that change the subject’s size category.

So it's rather unfortunate how this racial trait is worded. If it had used the wording from the previous sentence on "special attacks based on size", then it would stack.

However, if you find an ability worded in such a way, or similar to that, then it would stack with the Titan Fighter/Mauler's ability.