Daliz: ^ Those are quite easy to run with Wine so if GOG will do Wine packaging, BG-series should be the first ones I think (being that popular).
Future_Suture: What did GOG do to get them running on Mac OS? Or do all these titles exist for Mac OS natively?
AFAIK the Mac games on GOG come in a number of categories:
1. Already existing Mac ports that GOG have gained the rights to distribute.
2. Dosbox and ScummVM games.
3. Games wrapped in Wine or the like.
I bet it will be basically the same when they add Linux support.