Regarding RE3:

Does the Seamless HD Project for Sourcenext work with GOG? Has anyone tested?

There's a massive topic talking about it, but yes it works. Download in Japanese, then use the Sourcenext 1.10 .exe in conjunction with Classic Rebirth. Then, install as usual.

Don't think I can post links, but scroll down and you'll see a 4 page thread with all the links you need. The conversion patch is unnecessary, though.