I am playing a 1v1v1v1 game and I was wondering what would happen to my territories when I resign? I assume they become neutral but are they neutral with just 2 troops or with the number of troops the countries had when I resigned?

they become neutral maintaining the exact number of troops each terr had when you left it.

Unless you check "Players become AI when surrendering"
Then players become a Computer controlled player after surrendering.