I never had the PC version of Bleem, but I can confirm that a burned copy of Metal Gear Solid worked for the Bleemcast port of it.

My parents wouldn't let me buy M-rated games, so the easiest way for me to play MGS was on my Dreamcast with a copy of Bleemcast that I found used at Gamestop for four dollars with a pirated copy of the game.

I'm afraid I don't recall. I feel like it probably did if it was possible, as a defense against being called a piracy tool, but I'm not sure if there was any way for a consumer CDROM to check for the wobble groove. I owned a PlayStation and official games so I only recall using those.

P.S.: Some googling suggests that it played "backups" just fine.