Just that. I use Linux, so I don´t feel like risking buying the games if they won´t work under my system. I don´t really care about the "redux" version, but GOG has a history of providing the DOS versions for their games which I could run under Scummvm. Is this the case?

They are not included as extras, but I think you can indeed extract the old games from the Special Editions to play with ScummVM, I'm not sure how to do that, though, perhaps you may find instructions here in the forums or through a quick search online.