Yes, to your question about self-compatibility. The trick is to find the pollen! Adeniums are weird plants in every way. I don't have a photo for you, but if you google images adenium flower pollen, there is a cut away photo of the structure. The pollen is inside a sort of teepee, and the pistil, female part, is separated by a fleshy sort of bit, so generally the flowers don't produce seeds. Youtube has a number of videos about pollinating, all are for using two flowers, but you could adapt to one flower. I use an exacto knife to slice open a one day old flower to pollinate. I try to cause as little injury as possible. I transfer pollen with a tiny paintbrush that artists use to paint miniatures.
A bundle of flowers on a tall arabicum