"Thanks! If you don't think this is a good plan, we need to seriously reconsider."
I'm no authority, just one person with some opinions : )
I have never camped in blowing snow in any shelter so I don't have a good opinion about that, but that's not that common in PNW. I think you can pile up the snow around the edge which would keep out drifting snow.
In the PNW the problem is it can rain a lot, in which case pyramid is best because there's a lot of headroom so you can spend time under cover without feeling claustrophobic.
One of my (many) favorite places is the West beach of Olympic Peninsula in the winter. Ozette to Sand Point and Cape Alava, Rialto Beach, Toleak Point to name several. It rains more there than Seattle, so you have to watch weather reports and choose a time when weather is better. And look at the tide tables because you have to walk along the beach which is difficult at high tide. See http://www.portlandhikersfieldguide.org/wiki/Washington_Coast_Hikes