Somewhat tricky to answer with the ISL having just come out.

Recently SFO 737 F/Os assignments went unfilled on the UA side. I think 737 F/Os went unfilled at all the CAL domiciles and I believe that EWR 757 F/Os went unfilled as well. A legacy CAL guy can speak more about exactly what has happened with their bids.

As far as IAD goes, it has been pretty junior in recent years. However, at this point it doesn't have a 737 domicile, so if you were to get a 737 assignment to someplace else, you would need to have them open a new domicile there, or you would be stuck with no way to transfer. It does have a 320 base and a 57/67 base, so either of those as an initial assignment would at least potentially allow you to transfer bases and get to DC.