You do realize that all these characters are drawn to look bizarre, so the rabbit ears are added for that reason, don't you?
Plus, "Kotohime" means "Little Rabbit Princess", and she claims to be a cop, thus explaining the military hat.
And also, the flower markings on her kimono are the same as Kotohime's.
Yeah, but there's no rabbit monster in OFF. I would remember it.
That being said, Reisen doesn't have a kimono, and she doesn't have a bow in her hair, so there's a slight and minimal chance of you being not totally wrong.