USC Thornton would be a fantastic — dare I say the most fantastic — option for your daughter. That said, please know that the pop music program has a track record of giving little to no scholarship money, especially compared to other Thornton majors (including jazz performance). Would hate for you guys to have sticker shock.
Also, don’t know if you guys visited CSULB Bob Cole or CSUN. Both have solid jazz programs, and CSULB in particular has a very long history of strength in vocal jazz.