Would this work:

I have 5 army anyones in play, Sugar Man, and Jean Grey, Phoenix Rising is in my hand on turn 5. I pop A Moment of Crisis, naming Jean Grey. I use Sugar Man to KO the 5 Army guys and drop Jean. The dead Army guys are Jean Grey Cards, netting her 5 +1 ATK/ +1 DEF counters, yes?

No, they made cards saying Jean Grey meaning that it would need to be named jean grey and so on and so forth.

This was brought up with teh MTU ghost rider and ghost rider cards.

No, for two reasons.

1: A moment of crisis says "Characters you control gain the chosen identity this turn" a character card in your KO'd pile is not a character you control so does not have the Identity Jean Grey any longer (hats and clouds...)

2: Even if they did have Jeans identity, "each Jean Grey card" translates to "each card named Jean Grey" so mearly having the identity jean grey is not enough to satisfy pheonix risings power.

Nice Try but it doesn't work - Sorry

Drat. I'm shaking my hands doing the Revenge of the Sith NOOO!!!!

While we're on the topic, are there any silver or modern legal methods of renaming an in play character?

In play? Yes, mystique, but not in the KO'd pile.

You can't rename a card in the KO'd pile in any format, and there is only like 3 that rename in golden. And 2 of them are for army dooms.

Do Doom-Bot Corps remain Dr.Doom even if they get KO'd. Or does changing Zone make the card "Forget" what it was before?

"Pay 3 endurance -> If you don't control a character named Dr. Doom, Doom-Bot Corps has the name Dr. Doom and loses all other names and versions this turn. Use only once per turn."

I am fairly certain that when a card changes zones it becomes a "brand new card" in essence

Thats what I thought