Do you see any issues to put freestand tub above the 3 joists that drilled 3 1/2" holes.
Doesn't look great to me.
It will likely deflect or break over time.
You should have triple the joists and taken the pipe down the wall, not in the middle of the span.
No promises, but you can try removing all of the plywood, glue and screw two new layers of plywood over the joists, the wrong way (i.e. longitudinally).
Lots of glue PL Supreme, and lots of 3.5" screws, two layers.
Carefully lay out the plumbing design on top of both layers so you don't screw the plumbing.
As always, easier to do it right the first time.
Search the TrustedPros directory and discover the best contractors in your area.Find your home service pro