I honestly think that if the game was any good it could be done without copying Nintendo's IP. Just swap out the sprites and slap a new name on it.
Hell, that should be the plan from the beginning. Make it a "clone" or whatever in order to get attention, then once you get the attention and the legal slap dump out all of the Nintendo stuff and make it your own. If the core gameplay and story is any good it should still stand on it's own even if the setting and characters change. Otherwise then it's nothing more than a small step up over the CD-i games that we all pretend to like because it's new or something.
Hell, that should be the plan from the beginning. Make it a "clone" or whatever in order to get attention, then once you get the attention and the legal slap dump out all of the Nintendo stuff and make it your own. If the core gameplay and story is any good it should still stand on it's own even if the setting and characters change. Otherwise then it's nothing more than a small step up over the CD-i games that we all pretend to like because it's new or something.