Do not put a URL of the song up. I don't want anyone listening to your mix before they do their own.
If you want to edit, be my guest. Arranging is half of mixing so, of course you can remove what you deem to be superfluous parts. This is a mix, not an exercise in combining sounds.
I don't care if you mix it in 3 hours or 3 days. Personally, I'm mixing mine, like it were for a record. Do whatever makes you happy.
Hold on to your mix. I for one, haven't even recieved the tracks yet. An analog tape is being passed around for those mixes. We need to give everyone a chance to do their mix before we consider compiling them. Including me.