Just throwing some disguise ideas out there:
Good: SFoSM Puff Adder/Cottonmouth, CWOP Jester

Stupid: SFoSM Stilt-Man, JW 060 The Joker (50pts), UXM Uncommon Magneto

So do I get to roll for shape change if I roll 1-4 and replace chameleon as the target of the attack?

If one of his disguises is active, yes.

Watx Cerise will be an excellent disguise for him hehehehe

For Golden Age events I think I will include Beast Boy (In Gordanian Form). Following turn can bring in the T-Rex w/ +1 to a stat.... :-)

Bat phreak not sure you can do that. There is wording that suggests diguises can't be replaced.

The piece says

The disguises can't be replaced

So replacing beast boy with the T. rex would not be aloud

question about chameleon. if he is holding a weapon and switches to a new disguise does the disguise drop the weapon or does it remain held?

what happens if chameleon was on say, click 3, and gets healed by earth x jackal? the degeneration tokens dont let it get replaced, so would it just take the attack and stay, and if damaged get the degeneration damage, remove tokens and if it gets targeted again, gets another chance to go away?

Its unequipped, wheter it is only dropped or it breaks, depends on the equipment itself