I'll be arriving from Houston to PEK and transferring to Changchun with a 2hr55min layover.

Yes, generally speaking, you'll have enough time to make this transfer. If your both flights are in the same terminal building, you will need less transfer time.
By the way, the correct procedures are the following:
Inspection & Quarantine, Exit and Entry Frontier Inspection - Baggage Claim - Customs Inspection - Going through Transfer Formalities - Security Check - Waiting & Boarding
There are many English signs at the airport that can help you find the direction easily.