Do any of the doors lock when you use the fob?
Do you hear any sounds when you use the fob or the dash lock button.

I think that the new SKREEM/door lock module was not programmed correctly to match the VIN or something like that.
I think the SKREEM was replaced, along with the ring around the ignition key hole.
Both keys should act the same, which key did you leave with the mechanic? Are you sure that the key that half works is the original key you had prior totaking the car in?

The air bag light comes on if the air bag is disconnected without the battery being disconnected first. It has to be reset by the dealership.