I just checked and the Seattle Humane “MaxMobile” happens to be scheduled TODAY (Friday) at 2 locations in West Seattle. 11:00-2:00 at MudBay in Admiral and then 3:00 – 6:00 at Westwood Village Pet Pros.
You could also check in with Next to Nature in the Junction — I adopted 2 cats from there a very long time ago (they have had the sweetest family of black and white cats for so long). Might also check in with Kitty Harbor near Luna Park, I’m not sure if they adopt out between open/public events. Good Luck!