Just tested, and yes, you get glancing blow damage in bear for regardless of weapon type (got them using a dagger and unarmed).
On the other hand you do NOT get glancing blow damage with cleaves (like you do with 2 handers generally). I imagine that's probably vaguely not WAI, but I wouldn't count on it changing.
Other notes: Slivanus maul crit range does work in animal form. Swashbucking continues to not work (as the tooltips state, so WAI, but I thought I'd check since that would be sweet).