First thing I'm thinking is, why no access. How is someone going to check this for leaks before using, or work on it later?
The second thought is I'm not so sure that mounting a faucet in that position on wood is such a good idea, first time the stem leaks there's going to be rot oir at least stained wood.
My third thought is whos idea was it you use T & G wood as the top, for a soaking tub? Waters going to just lay in the low spots and leak down below it and the woods going to mold up.