We would appreciate if NEW covers are made specifically for the zine. That being said, if it was not posted anywhere, there's no way for us to figure out if it isn't new. So while I highly recommend making something new, I can accept it if it wasn't something posted publicly. Secondly, yes, due to the fact that many siinamota songs don't have official instrumentals, vocal removers can work for covers. Thanks for the questions! (Questions sent through Interest Check)