Ok so i asked Stacy the guy i use about stems etc:his reply.
"Yes,
As an optional service, for $75, we compile and consolidate all the final takes into individual wavs, zip them up, and send them to you so that you can have others use the tracks, re-mix, re-record, re-master.. however you want.
Many studios don’t allow this, but we do. You can treat our productions as work for hire masters, without having to pay master scale or any extra “buyout” fees.
But you’re right, studio musicians do not need stems or anything other than a reference worktape or production if they are re-recording it. They will hear everything by ear and then chart it out and play it."
Stacy – AWP