がくせいたちは / こうきしんがつよく / ねっしん / だった
The counterpart of the "curiosity" is こうきしん, and there is no general adjective meaning "curious". So when you say "curious", こうきしん must be followed by some verbs like (が)つよい or (が)ある. And the counterpart of "enthusiastic" is ねっしん(な) or むちゅう(な).