1) When I'm in Toronto, can I go through US customs at Pearson?
2) Can I get a boarding pass for both Air Canada and Singapore Airlines at the same time when I check in and get my boarding pass for Air Canada?
3) Since my final destination is Seoul, when I arrive in San Francisco, do I need to pick up my luggage again and check that in with Singapore Airlines? Or will Air Canada take my luggage directly to Seoul?
4) My arrival time in San Fran is at 11:15am and departure is 12:50pm on the same day. Is this sufficient time?