I'm replacing the counter tops in my kitchen with granite slab. I'll
be removing the old counter tops myself, and installing the plywood
foundation over the existing cabinets.

Are there any issues with driving in fasteners from above the plywood
rather than below?

Most everything that I've read calls out fastening from below. For
most of the job I will be able to do this. However I have a raised
bar area (4" wide x 72" long) that is drywalled on both sides, so I
won't have access from beneath.

Thanks,
Brian