1989 360 Factory Roller lifter question

I have recently aquired a .030 bored 1989 360 block (LA, not Magnum), set up with the factory roller cam. I am going to stroke it with Stage 2 Indy-Eldy heads and an M1, so I won't be using the factory cam.

Question:
1. Can the used roller lifters be used with a new cam? (they appear to be in good shape)
2. Are they ok for performance applications?
3. Should I buy new Mopar roller tappets, or just go with a flat tappet?

Thanks!