Indeed. Yhere is a lot of potential there.
Grant Morrison tried to do it in Seven Soldiers but Frankenstein was the chosen one in the end.^^^I think your choice of The Demon (a human w. a monstrous barely controlled oddly colored alter ego) would really work better as the Hulk.
I kicked myself for not seeing that!
Now, to your Kirby Defenders, I oposse... Ditko's Defenders!! (AKA the Unity, but I like more Atlas Force):
Unity.jpg
The cosmic powered alien, the royal from an enigmatig realm surrounded by darkness; The man who can change himself and reality (and change is magic); the man with an uncontrollable monster inside him; the sworder with an strange relationship to death; an urban vililante who is the odd man out of the team.