Edit: Whoops. I see now that the OP was going to Quito, Ecuador, so that's not included in the list of South American nations for access. I'll leave this here as it might be useful for others.
No lounge access at SFO or UIO. We used our priority pass - but again bad for COPA not offering lounge access to outstations
Thanks for the report. Regarding lounge access, maybe I misunderstand United's access policies, but it seems to me that you had access to the United Polaris Lounge at SFO via your business class ticket on Copa (Star Alliance):
https://www.united.com/en/us/fly/tra...ge-access.html