Crane Cams 1.7 Roller Rockers

1.) I don't know, maybe from Crane would be the best bet.

2.) Are your heads pedestal or stud mount? I don't see aftermarket ones in your sig, so I'm gonna assume they're stock pedestal mount. It's possible you'll need shims. I think if you had a stud mount setup you wouldn't, I think shims are only needed with pedestal mounts.

3) Stock pushrods should work just fine. The main thing that effects if you need longer or shorter pushrods are heads. (TFS heads usually need longer pushrods)

4) I think fox body valve covers are known for fitting 1.7 rockers under them, but somebody else should know for sure.