With the help of a dear friend who's a 1960s Delta Zeta alumna, looking through old UT yearbooks, and researching property records, I think I've determined the fate of the final houses of all the NPC sororities that are no longer at UT. I'm about 95% certain I've identified the location of each house, and they are no longer owned by those sororities.
Phi Mu - the building still exists and is now owned by a tutoring business.
Delta Zeta - the Kappa Delta house is now at that location. DZ sold the property to KD in 1980.
Phi Sigma Sigma - the site is now an apartment complex.
Delta Phi epsilon - the site is now a condo complex.
Alpha Gamma Delta - the site is now a condo complex.
Alpha Omicron Pi - the site is now a UT building.
Gamma Phi Beta - as I mentioned previously, our house is now an apartment complex.
History and architecture are two of my interests, so this was a fun little project!