IANAL, so take this with a grain of salt. Cover songs are always legal to create and belong to their authors, no matter how famous the original. If you use such a cover in one of your games, it's the cover's author you have to deal with. That said, cover authors must pay royalties to the original's copyright holder. (It's the other side of the coin.) If they license the cover in turn to someone else, it might complicate matters. So check the terms, if any, and if in doubt contact the cover's author!