It depends on how important it is to travel to China next week, but it sounds as if it's important. So, in your situation, I think I would (1) call UA and explain UPS lost my passport so I would like to have SFO-PEK only moved to Saturday, hoping they might waive the fee; (2) plan to arrive Friday either 8:15a [wait in line] or 9:30a [wait out the initial rush] at the consulate and request a same-day visa, with extra care to bring all the documents.
I think you'll have trouble with SDC since there's only one daily SFO-PEK flight.