I'd head out to SeaTac and get global entry just to help with passport control. You have to make an appointment as I understand it.
http://www.globalentry.gov/
I've made it from landing, through passport control, picked up bags and re-checked them and on to an AS gate in just about an hour (it was just as the door closed, however

) so I think 2.5 is okay unless you're late. If you're in 1st on Alaska, you probably won't get it on a re-booked flight if you miss your connection but that's not a huge worry.