Yeah, I'd rather avoid getting other forums involved in that capacity as I don't want to deal with moderators or having to police another forum's lists. I'd rather people post here (it's not difficult to make an account, and they don't have to stay. George and I don't make money on traffic, so this isn't a ploy to increase visits... though if people stay for SEGA discussion the more the merrier).
Re: Knuckles in Sonic 2, I think we can just consider that to be a part of the Sonic 2 game. Doesn't need to be mentioned on lists, but it is an expansion of the game and can be deemed a version of it just as Sonic 2 iOS and 3D Sonic 2 all count toward Sonic 2. I should also note that a bad port does not invalidate a game's quality. The original iOS Sonic 1 and 2 and the GBA Sonic 1 are crap, no question, but the game itself is the focus and if the game exists in a better state then obviously we are referring to that. The core/base/original game.