Cool to see that there's some interest. Your points are very fair, Sheepy. I think we could address them, though.
First of all, we could account for availability of the games by adjusting the time frame. If someone wants to sit out a game, he/she always can. Then again, I'd like the discussion to just pertain to the game since there's already a lot of collection and hardware talk in here. So while I would personally aim to obtain all the games we would play in physical form, I wouldn't give anyone the 'receipts.gif' card, if that makes sense. Especially since not everyone has the same funds or the same access to certain games (think PAL/NTSC differences, for example)
As for game choice, I can think of two ways to handle it. We just take turns picking a game. This would just be a gentlemanly/ladylike agreement between us, in the hopes that nobody gets mad. A second option - one that I like even better - would involve me making a poll and people sending in suggestions for the poll. Something like this for example:
http://strawpoll.me/4562808
It's not like we have to set strict statutes on everything, we can just go with the flow. As long as we check out some cool Gameboy games we haven't spent much time with before, I think we'll be just fine.