That would work. Quite deep when you add it all together including adhesive and tile.
You realise the amount of work involved, and it would be cheaper and less labour intensive using a worktop?
Look at the recommendations of the adhesive you will be using. It should mention a primer or sealer. The ply expands and contracts with moisture, so stop the moisture getting to the underside and sides of the ply. You normally don't seal the top surface as the adhesive does not adhere as well.