Not at all, people want it on GOG because 100% of their games are DRM free. It's a big focus of their marketing, and if Eternity appear there you can be 100% sure it's DRM free too.
Not really. Any new game released on Steam require the Steam client to run. Bethesda Softworks made a mistake about that with Skyrim, only making the SkyrimLauncher.exe require the Steam client and not Skyrim.exe itself, but it was quickly fixed with a patch.
Also, the Recettear FAQ state the following.