[Goggen]

Originally Posted by D2

Spoiler for Hypothetical question:

Is it at all possible for the Another to somehow survive the entire school year?

Yes, because that's what always happens. With only two exceptions,

Spoiler for later episodes:

Reiko's class and Kouichi's class, the Another died those two years. Normally, people keep dying until the end of the school year and then the Another goes back to being dead.