Hi there!
Visiting Fuji and Hakone can be difficult if you don't prepare before hand as there are different transport companies and methods involved.
1.) Arriving late at Narita Airport is not ideal but you can still travel to Tokyo and Hamamatsucho. Here is the route.
2.) You can purchase the Kanto Pass at Narita Airport or Tokyo station.
3.) You can buy the pass at any time and start using it right away, so I would recommend buying it on the day that you travel to Gala Yuzawa. The Kanto pass does not cover travel to Odawara so you may be better off buying the Hakone Pass and travel from Shinjuku station in Tokyo. The full coverage can be found here.
4.) Fuji (if visible) is beautiful from every side! Choosing an approach (such as Kawaguchiko or Hakone) is better based on what else you would like to see and do in the area than just for a view of Fuji.
5.) You can visit Hakone (and view Fuji from there) as a day trip, however there's a lots to see and do in Hakone, so make a plan(ing) beforehand.