All-Out Assault: Once per game, give Iron Man/War Machine a power action that places two action tokens on them. Iron Man/War Machine possess for this action. They can make up to 4 close and/or ranged combat attacks as free actions. An opposing character may only be targeted once during this action. After resolving this action, Iron Man/War Machine are dealt 1 unavoidable damage.

Adaptive Response Armor: When Iron Man/War Machine uses the Duo Attack ability, they may choose Incapacitate, Penetrating/Psychic Blast, or Ranged Combat Expert and use that instead of one or both ranged combat attacks.

Can Iron Man/War Machine use All-Out Assault if they already have one action token?
No. You must be able to place two action tokens on Iron Man/War Machine in order to use this trait and if they already have an action token, then you could only place one more token.

All-Out Assault says that Iron Man/War Machine can make up to 4 close and/or ranged combat attacks. Does this mean that they can make a ranged combat attack against an opposing character when they are adjacent to another opposing character?
No. While this trait does allow this character to make more attacks than normal, those attacks must still follow all normal rules for close or ranged combat. If there is an opposing character adjacent to Iron Man/War Machine, then it can not make a ranged combat attack.

Can I mix and match the powers in Adaptive Response Armor? For example, could I use Ranged Combat Expert for my first attack and then Penetrating/Psychic Blast for the second attack?
No. The power says to choose Incapacitate, Penetrating/Psychic Blast, or Ranged Combat Expert and use THAT instead of one of both ranged combat attacks. The "that" is refering to the one chosen power: you can choose Ranged Combat Experta (as an example) and then use Ranged Combat Expert on the first attack, the second attack, or both attacks, but since you chose that one power you could not use either of the other two.