"Was Hamas attacking Isreal after Oslo and before 2nd Intafada?" Yep. Egyptian and Jordanian governments have enough power and control to suppress their fanatics and honor their agreements. The Palestinian government is partly controlled by fanatics. Any concessions from Israel will be contingent on either Hamas accepting what Abbas agrees to or if not, Abbas having the power and will to crush them. Even Jimmy Carter said Palestinian militants will need to be taken out by force if they don't get with the program.
4 UN peacekeepers injured in Sinai and taken to hospital in south Israel (Haaretz)