Good news first: It is possible to publish cover versions, remixes and edits via recordJet.
However, where you have to obtain the necessary rights depends on whether it is actually a cover or an arrangement. As soon as you change more than just a few chords on a music title, the cover version becomes an arrangement and the rights cannot be obtained from the collecting society (e.g. GEMA, ASCAP), but must be acquired directly from the rights holders. The rights are usually held either by the artists themselves, the authors (composers & lyricists), the responsible label or publisher.
We recommend that you consult a lawyer to find out whether or not you need the appropriate permissions from the author. This way you can be sure that you will not be sued. As soon as you have clarified all the formalities, you can start publishing.
Please also note:
Lyricists and composers of the original track must be credited.
Album titles must not be misleading or play with the names of popular artists.
No genre designations, song lyrics or names of the original artists may be used as album or track titles.
Under no circumstances may the ISRC of the original track be used.
The cover artwork must not be misleading: no artist who is not involved in the release may be depicted or named.
For remixes, the name of the remix (e.g. “Skrillex Remix”) should be entered in the “Title version” field.
Important: Tributes (soundalikes), karaoke and Public Domain Content cannot be distributed via recordJet.