We needed open-jaw F/C award tickets IAD-YVR and ANC-IAD for a cruise in 3 months. With only 1 US Air flight per day out of Anchorage this wasn't going to fly. I found that I could buy cheap F/C ANC-SEA tickets on Continental and do the awards SEA-IAD as the return leg.

The questions:
1) I assume that I can't interline the bags at SEA since the Continental inbound flight and the UA ex-SEA flight have nothing in common (different PNRs, different carriers) but would like to find I'm wrong.
2) Continental flight arrives at 5:00 AM. Two UA options available. The first departs at 7:20 AM via Denver and gets to IAD about 5:30 PM, while the second leaves SEA at 8:30 AM and arrives at about 7 PM. Obviously, getting home earlier is preferable, but assuming the answer to 1) is no, we'll have to claim bags and check back in through security and all. I haven't been to SEA for decades (literally) so have no idea of efficiency of their baggage ops or the layout of the airport connecting from Continental to UA. Advice? Experience? Thanks.