Shortly after he moved in he managed to put a foot through the fiberglass bath tub, which we replaced with a cast iron tub. 

Mold testing revealed it in the ceiling of the basement, water damage was evident when the fiberglass insulation was removed. 

You can get 4 piece fiberglass shower shells that will allow you to get it through the doors.

Fiberglass (pink) or Cellulose (brown).

Right now I am looking at Aker CM-60 fiberglass for around $420Aker ACCTS-3360 acrylic for around $800Delta 226032AL00 "Acrylic" $500 (although I've heard that it is just an acrylic layer over other material).Any suggestions of different units or recommendations of things I should be avoiding?

My windows are pretty shot so I am getting them all new, $8,000 for whole house vinyl or $12,000 for Marvin fiber glass windows which may work better for resale and less repairs in the future.

Austin is really hot and all my rentals are 1980's built and we blew about afoot of loose fiberglass insulation in the attics to save wear and tear on the ac units as well as keep the tenants bills lower.

I think fiberglass bat is R19 off the top of my head. 

At the time, I did not want to wall off the window, install a vent and spend the money on a good fiberglass surround because I was doing a total rehab by myself and I just knew I didn't have it me.

It is insulated in the foam case and fiber glass against the wall anything else I can do?