Chaco Canyon Cafe would be a great place to go. It's in the U District. www.chacocanyoncafe.com/
It is not 100% Vegan as it claims on their website. I have seen items there that were not Vegan. I don't know that there is anything that's non-Vegetarian though, but I seem to recall some animal-ingredient dishes when I was there last (can't be too sure though, sorry)... Still, there should be enough there to satisfy everyone.

Another thing you could do is have a papaya salad w/out the fish sauce or dried shrimp & peanuts @ a Thai Restaurant, while everyone else enjoys the non-raw/non-vegetarian meals. The server may think you're crazy for ordering that way, but they should be able to accomodate you. A Thai restaurant also ought to have fresh mangoes during this time of year, so you can even get a plate of that to sustain you while you're there.

Oh, another good option would be Tilth. You may end up having to get a salad, but it's not just your plain old salad. It will be amazing with the freshest organically grown ingredients right out of their own gardens or from local farmers. tilthblog.wordpress.com/about/

I have always loved The Teapot on 15th on Capitol Hill

My favorite vegan Restaurants in Seattle are yes, Chaco Canyon, Pizza Pi , Araya's which is a vegan thai restaurant, and the Wayward Cafe which is a punk vegan collective. All of these places are in and around the University District. You should be able to google them quite easy. These places all serve amazingly delicious vegan only food. In Joy!