Ken, They look to be in great shape. The one being taller is not a problem. Think of it like children and their parents. Not all children will look like them and come in all different shapes and sizes, much as the Adeniums.
The more bulbous root will form under the soil as well as noticeable amount above as they become older.
Rick

Rick. I have enjoyed watching my "babies" grow. If not for the kindness of @Ursula sending me some seeds, I would have never grown these plants.

So cute all of them, Ken! Yeah, got to keep them just a little moist this winter, they are all young. I love that fat one in the middle. As Rick said and I have already shown to you in a photo, it will do some more of those interesting root formation below soil level, so you can choose to raise it a bit later on to see the art form down there. Good you have the solarium for them, so this winter they can get all the warmth they can have. Just watch the leaves, sometimes even if it is still there, the plant may have already been semi-dormant.

I usually find my Adeniums wake up ahead of my Plumerias after overwintering. So when both are in dormant mode, I use my Adenium as a basis if temps are starting to improve.

Tarev. Of the six or so plumeria I have inside, only one has now begun to get some yellowing leaves. That's the "historical" seedling, Kathryn's Honeysuckle Rose. It will be interesting to see what level of dormancy they all go through over the next 3-4 months.

I remember the first time I overwintered my Adenium, made me feel like going on panic mode after all the leaves dropped..really bare..feeling the caudex, firm and hard as a rock, so that was reassuring. So I went on reading to find out it is just normal dormancy phase. But there is beauty in its bare form, especially if the caudex is visibly showing already, so now I appreciate the dormancy phase. Gives a better look at the entire plant form hidden by the leaves and blooms.

I will be watching for leaf-drop. Growing leaves now.