Hoping to get a couple questions about RUCs answered...

1. How does the waitlist work with companions? If 2 people are waitlisted and only 1 seat is released into RUC confirmable inventory, does only 1 person clear?
2. I am hoping to use an RUC on SJU-ATL-LAX-KOA. It looks like SJU-ATL is likely to clear as a complimentary upgrade anyways whereas ATL-LAX and LAX-KOA will be tough. Is it possible to waitlist only for the ATL-LAX and LAX-KOA segments? And if only one clears, will I stay on the waitlist for the other segment?

Thanks!