Almost all of them. There's a list on the interwebs, I'm sure. One I remember not working well is Toaplan Shooting Battle (runs at like 1/10th speed) and I think one of the Namco Collection games.
It shouldn't be, unless there's hardware differences. I doubt an incompatible game disk will run on any region affected ps2 model (assuming you're gotten around the lockout).
Again there was one (in Japanese) floating around. There is one for American games, but for ones that were released in Japan, these also don't work.
thats the one i'm looking for the japnese one. do you have copy or a link? i want to import a japanese ps2.