Is it okay to mix neoral (cyclosporine) and gengraf?

Probably: It sounds as if you're asking about commercial bone grafting materials for oral surgery. If that's the case, it's very common to mix components to form a composite graft.

Bioequivalent: Both Neoral and Gengraf have been used in transplant recipients for many years (Neoral ~30 years, Gengraf ~ 10 years). Gengraf is an AB-rated generic cyclosporine for Neoral, and has been shown to be bioequivalent in several studies.