Talking to the owlbear and using animal handling on it is fun and interesting and makes for an exciting encounter. To hells with specific creature types in such a scenario. Ask yourself this: in this specific encounter, is it really so important what the exact creature type is, and would it be worth it to remove it from the game altogether for the sake of sticking to this rule? I would answer this question with no.
To quote myself "Not that it really matters in the grand scheme of things..."
I would argue though that no, being able to talk to the owlbear adds NOTHING to the encounter. You can't talk your way into being able to assist it and retrieve the spear point peacefully. Nothing changes other than getting a couple lines of dialog from a monster.
