For what it would cost for an adapter, which would introduce additional lag, you can just get an HDMI-based Flashback or equivalent (My Arcade, etc.), and have a better experience. If you really want the adapter, an OSSC series or Retrotink series are probably your best low-lag bets, but there are cheap composite to HDMI adapters out there that do work as well. Just make sure you have Game mode enabled on your display, although again, that doesn’t mean the conversion won’t introduce additional lag.

Ahh… good ol’ Activision, they still have the rights to it. You’ll have to add it yourself.

Yes, the Gamestation Pro can play additional games that you add to it via SD card. You have to decide which version of those games you want and download the correct format file from a reputable site (keeping in mind that certain games are not in the public domain or abandonware). You can just do a simple Google search for instructions, as it’s too involved to describe here (you can also purchase pre-made SD cards, but it’s really something you can do on your own and there’s no guarantee that the specific games you want will be on the pre-made SD cards anyway). Obviously, make sure you install the latest firmware on the Gamestation Pro as well, as it helps with lots of things, including compatibility.