I have a concrete slab, and am about to install 5/16x2 1/4 solid cherry. Would I be safe applying MVP to the slab and then fastening plywood over that. Then nailing the floor to the plywood. I would like to nail the floor so if there were ever an issue it would be easier to make repairs.

You would need two coats of MVP. 5/16 is usually a gluedown only. It is very temperamental to fasteners, unless it is top nailed.

Do you mean glue down to the plywood or to the concrete. I would like to minimize all of the risks associated with glue down on concrete. BTW I am in Houston.

Bruce/Hartco make a 5/16" x 2&1/4" that can be successfully/nailed stapled. I imagine your cherry floor can be as well. Double check the manufacturer's instructions. You will need a Floor Runner type of stapler or a Power Nailer Model 200 or similar. On the other hand, I see Floorguy's point that spending the money and time on installing plywood seems counter productive. Just apply the MVP then glue the 5/16" flooring down. A concrete moisture reading is MANDATORY, especially when installing solids.