Vincent--don't count on that bonus. You'll get your 100% EQM based on fare class purchased. When I took a bump on an award ticket earlier this year my new BP also said Y, but the system was smart enough to know I was not to receive any mileage, let alone 150%.
Regarding Seattle, absolutely plan to go back whenever you have the chance. It's my favorite U.S. city. And while it is normally cloudy outside of summer/early fall, it actually gets less rainfall than NYC.