I'm extremely happy to come about a site that brings our favorite old games to us in a digital format. However I'm slightly handicapped in terms of a computer, and only have a Mac at the moment. I'd be curious to know whether these games will be released for OSX as well sometime in the future (especially the BG series)?

I can't answer your question, but since you are a Mac owner you can play Avadon:Black Fortress right now, which makes you a very lucky bunny in my book.

Here, try reading this.

You could get the DOSbox and SCUMMVM games running. The problem is the installer. Meaning you'd need bootcamp or similar to get over that hurdle. But then you could probably play most GOGs through that.

Or just some app like Universal Extractor (but for Mac).

Well yeah, but I wouldn't know what to recommend in that regard.

Universal Extractor works fine in Wineskin. As a matter of fact, if any game works in CrossOver Games, it should work in Wineskin with little or no difficulty.