It sort of HAS to be a remix. :
Then it's not a cover. Also, a remix calls for original material to be used. If this is a COVER compilation, the COVER should sound like the original. Otherwise it's an "acoustic re-version" Or something
I agree with Bit Shifter, I can show you 4 different versions of each one of my tracks that are extremely different to each other and all done by me. Unless you are super narrow, re-interpretation of your own material should be cool and varied.
In any case, sounds interesting, if I had any recording gear, I would participate, then again, I have no instruments anymore, they take space ;P Maybe I can lend a piano somewhere...