Seems sensible, I agree with Baja, not that I do it...hehe. I always give my plants a light water to settle the new soil around the roots (light), my heavy watering is just enough to let the water drip from the bottom...in any case, never had issues, so will do it, but the safer option, especially with no leaves is to wait. I must also add, that when I transplant I do not play, I have everything set and it's all done in a minute, comes from transplanting lots of succulent babies...hehe.
Those are really nice plants newtonsthirdlaw. I would definitely wait until the growing season starts before transplanting. The only Adeniums I have lost have been in soil during the winter. I should knock on wood before I say this but since I have had mine in s/h I haven't lost any. (gulp, looking over my shoulder...)
I would just let those beauties rest for now. But good luck for sure.
If you look back on this forum there is a lot of info on S-H. I was at my local hydroponics store recently and they carry the "fired clay balls." You might check your local stores to save the shipping.