Bag Check In for ATL-YVR

Hi all - A couple of quick questions,

I have not yet traveled to Canada out of the states yet but will be in a few days. Routing is ATL-LAX-YVR.

1. Since the first flight will be a Delta domestic and probably use a A\B gate, am I required to check my bags at the international terminal, or can I use the baggage drops at the south terminal domestic check in?

2. The LAX-YVR segment will be on Alaska while ATL-LAX is Delta. Since it is all Delta coded, I assume Delta will tag my bags to YVR in Atlanta, and they will transfer from the Delta flight to the Alaska flight automatically?

Appreciate any clarifications!

Thanks!