I mean, I know they're defunct and all, but like, who owns the rights to games like "Arcade America" or the Monty Python point-and-click games?

Panasonic Interactive Media bought the distribution rights to the Python games, but AFAIK, that division of Panasonic doesn't actually exist anymore. I would guess that Panasonic itself still retains the rights to those games. I think Take 2 has the rights to everything else 7th Level may have made.