An Alaska trip is very port intensive and in the summer their are lots of families on board. So I would go with the line you want. I perfer Princess in Alaska because they go to Glacier Bay.
Definitely premium economy. It is a very, very long flight.
And you will not be able to make a 10:25 flight. You need to be at the airport at least 3 hours before flight for international.
Have a good cruise. Beautiful countries.