Translation:Are mice cute?
Is there a way to tell if the sentence is speaking generally? Why is "Is the mouse cute?" not acceptable?
It should be accepted. Suggest it!
Koreans usually don't use -들 for things that aren't people (in my experience).
는 makes it pretty general and if there's no specific mouse both the speaker and listener know, I would assume that the sentence is meant in a general way. Nevertheless "Is the mouse cute?" should definitely be acceptable here.