Amalgamations are a tricky one. Personally, I don't have as much of an issue if it's something like Green Lantern or Dr. Fate; when the powers are tied to an [i]object[/i], who's to say that a Marvel character wouldn't find it before a DC character or vice versa? But I always try to keep it in the realm of "which characters run in the same circles?" Carol Danvers is a perfect Lantern, IMO, because she's already so tied to space. Many of her allies and enemies transfer over. But something like Matt Murdock GL? It's trickier.