can i set an undermounted sink on plywood than place granite over thatm?
Answers:
Plywood should not be required as an underlayment for granite. Plus after you put the top on you will see the plywood edge. My suggestion would be to undermount the sink directly to the granite. However, there are special tools and adhesives used in granite fabrication so you may need to leave this up to the pros.
Other answers:
no
no
you can, but why?