I am installing a whirlpool tub into an alcove, where the center wall
is an exterior wall. There is room to have about a 6" surround on each
side of the tub, or I could have it off-center and go up to 9" on one
side.

SWMBO wants the fixtures on the middle (exterior) wall, and I'm trying
to decide if it's even possible with a topside plumbing access. Not
only would it have to be large enough to facilitate installation and
potentially repair, it would also still need to seal.

I'm building the surround out of some leftover brazilian cherry we
have from the stair remodel (I build box newels for that).

Is this possible, or is it just as bad of an idea as it feels like?
Should I consider an outside plumbing access? This is a 2nd floor
master bath, stick-framed, with a brick vernier exterior.

The other alternative is to just install the fixtures on the front
side, but you'd have to get in around them, and they wouldn't be as
nice to look at.

Thanks!

-Mike