Welcome, and hi (again, I "saw" you elsewhere! LOL!) The name C. arborescens should go with the 4th pic, as a suggestion from me. The 'Sorrento' name was also a suggestion of mine, but without having seen its' bloom, there's no way to confirm that from these 2 pics. As a likely hybrid, it could be something else that looks very similar. There are so many of them just within Sedeveria. It could be an entirely different genus. Sometimes one has to have a plant around for a while before being able to be sure what it is. If your DIL has some pics of the plants with blooms that she could send for you to add to the discussion &/or compare to blooming plants of the suggested names, that could help.
Several types of C. arborescens:
http://garden.org/plants/searc...
Some Sedeverias:
http://garden.org/plants/searc...
A similar (to your reddish plant) Graptosedum
Graptosedum (XGraptosedum 'Bronze')
The first one needs the most light, IME. If at all possible/practical to keep outside for summer, I recommend it. It looks like it just came from being very near a S or W window, or outside. If you start seeing this kind of look, with leaves pointing down at the tips and much farther apart on the stem, it's from lower light:
The other 2 plants are much more amenable to less light/being inside, though, as said, do need a spot where the sun can shine directly on them for at least an hour per day. As long as the leaves keep forming as closely together as they are now, the light is sufficient. Seeing some blooms in the next few months would confirm that.
