Transfer time for incoming Air China from Shanghai to Air China flite to USA 3/4 hr.

1. For this domestic to international transfer both in T3 at PEK, you have enough time to catch the plane. Don't worry.
2. You are advised to consult the airline and ask whether they have luggage check through service or not. If yes, the luggage would be tranferred to the final destination directly.
3. Yes, by the way, the procedures are Flight Arrival & Transfer Procedures - Inspection & Quarantine - Exit and Entry Frontier Inspection - Security Check - Customs inspection - Waiting & Boarding