[@Master Bruce][@Lord Wraith]

I had a couple of questions about playing villains.

1) Can I assume villains should be treated as legacy characters?
Example - If I was interested in playing as the Green Goblin I would have to converse if the Spider-Man player (Master Bruce) before typing up a CS?

2) Are there restrictions placed on villain PCs?
 Are certain villains off-limits (Thanos, Adam Warlock, Darkseid)?
 Can a player turn a villain into a hero?
 Can a player turn a hero into a villain?