yeah, I've seen all of those. I don't think they offer any nectar, so I'm not sure what the payoff is for the pollinator. lots of critters eat pollen, but that only accounts for visits to male flowers. the female flower is an inch or so away from a cluster of male flowers.
taking a break on the deck just now, I heard some activity and strolled over to have a look at the akebia. there is a crowd of honey bees taking some pretty serious interest in the flowers. doesn't seem to be any pollen in their baskets, so maybe there is some nectar. they certainly smell good right now.
not the best photo, but there's a bee on an akebia flower.