I’m in Vancouver, BC, which is similar to Seattle but cooler. I agree that the varieties that you mentioned should grow well, except that I haven’t grown Methley. As far as taste, individual likes vary tremendously. I’m sure that my perception of good tasting fruit is very different from yours, because I consider Shiro to be the worst tasting plum that I grow. So, my taste recommendations would not work for you.
But, to give you an idea of what I really like, I tasted what was labeled as a plumcot last year and decided that it was better than any of the plums that I have. I think that the “plumcot” was actually the pluot variety Dapple Dandy, which I am planning to graft onto my plum tree as a replacement for Shiro. I have no idea if it will grow well in this climate.