They just finished framing the house, and I'm wondering what spots I should add insulation (either fiberglass or spray foam from cans). The exterior is 2x6 walls with blown in blankets and spray foam filling the rim joists.

Here is specifically what I was wondering about:
-Fiberglass batts in interior wall between powder room and dining room?
-Insulation around PVC soil pipe (the master toilet's pipe runs horizontal above the kitchen ceiling for 8 feet or so--I had thought they would put this in an exterior wall but apparently not!)
-Spray foam around penetrations through exterior sheathing (if not done already)?
-Insulation around hot water pipes from water heater?

Does the insulation for noise control make much of a difference? Anything else I ought to do before insulation is blown in and drywall put up? Thanks!