My husband just re-injured his right hand and our doctor has told him he can no longer shoot a traditional bow with finger release if he wants to mantain the use of his fingers. So he tried shooting with a mechanical release, but arrow flight is horrible off the shelf and the bows (Bear Montana/Samick Red Stag) became really noisy.
So the question is, do the Gamemaster/Dorado come drilled(?) with the option of adding on a compound style rest that will help us achieve good arrow flight? And if so what rest would work? Or does he have to convert whole hog to a compound?

Yes

I think it does.  My samick sage has the berger hole that can be used with a NAP centerrest flipper or similar rest.  I have even seen pics of a Dorado with a whisker biscuit on it.  Good luck and I hope your husband has a speedy recovery.

What rest would you folks recommend for use with a release.

A simple flipper rest with a Berger button should work fine.
                 Craig

Some of his flight problems may be from the release/string combination that he's trying. Put a second nock set about an inch below the one on the string right now. The arrow still goes under the top nock set, while the release grabs the string under the lower nock set. This should eliminate any torque issues. If you check in the newest issue of Trad Archers World magazine,there's an article on how I set up to use a release. I have no problems shooting off the shelf this way. So to actually answer your question, "No, he doesn't have to give up his trad equipment". (Especially if it's as important to him as it is to the rest of us here. Good luck.)