No to the second part unless some other character's creations eradicate them, or some other variable is applied. It's mainly just the dead character in question taking as long or as short of a time as they want to come back. So an example would be a character who got, say, erased from the existence of a jointly created universe and decided to slowly reform bit by bit in the white space rather than doing so instantly.

And yes their power would be endless, though that seemed to be the point of the initial post you made what with limitless creation, so I tried to keep it as intact as possible when coming up for a way for characters to not just instantly die when some edgelord makes a genocidal killing machine.