I think you are right about the pollination of the adeniums by the Oleander moths because I do see them go inside the adeniums blooms. I've had more baby seedpods now that I've seen a lot of Oleander moths and caterpillars in my adeniums. Aside of course from my hand pollinations. I have been transferring the caterpillars in our grassy patch of lawns. Not sure if they eat other types of grass.
I know I am not successful in hand pollinating the multi petals but noticed some baby seedpods on some that I didn't try to hand pollinate. Too bad, they will most likely just fall off, especially now that I stopped watering.