Thanks everyone for the replies. Sounds like she should be okay as long as she brings her boarding pass for the last leg (HKG to KHH) to SFO for SQ to help w/ the interline (wasn't aware of this term, thanks!).

I got the mixed results from searching the web and reading tripadvisors reports. Most of the responses were over 3 years ago so I wasn't sure if they were still accurate.

Thanks again everyone. I use most my points/miles for family, and I don't travel much myself. So I'm not familiar w/these transits protocols.