No, it is ok - no need to trim for a long, long time. Adeniums bloom best when pot-bound.

I'd suggest that it would be easier to maintain clearance for the solar panels to get full sun and also have a vine get big enough to screen the view from the street if you would consider adding a trellis/pergola to fit over the wall forward of the arbor, or maybe just a pergola over the gate area, and plant 2 15 gallon sized bougainvilleas at the front of the wall to climb up the new pergola over the gate. Trying to face the existing arbor with solar panels at the front with something as fast growing as bougainvillea isn't smart from a maintenance standpoint, you'll eventually have to prune it regularly to avoid shading out the solar panels. If you were simply to plant bougainvillea to climb up the walls from the front, over time, the vines could become at least 18 inches taller than the top of the wall with a bit of regular pruning, and accomplish the objective with no need for additional structure. Other vines/espaliered type shrubs that could do the same might include Grewia occidentalis, Podranea ricasolaena, Tecomaria capensis, etc. You might also want to consider framing the entry walk with another set of accent upright palms/accents such as Phoenix roebellenii or Strelitzia nicholai to repeat the formality of the Queen palms in the courtyard, and frame the entry while further screening the roof solar collectors.

How hot is it getting there? You could pot it into a 2 gallon pot, using perlite to give it drainage. When it is over 100º I only water my boug maybe every other day. It' better to schedule the watering to the plant's needs that just give it an arbitrary watering schedule. It likes to dry out a bit, so let it, then water it well again.

Softwood cuttings can be taken anytime. I don't have any success with them. You can take hardwood cuttings in the Autumn/ Winter Or wait six weeks or so till the softwood cuttings are a little firmer mid to late Summer. Cut off a piece, pinch out the growing tip, just leave two or three leaves up the top scrape the edge down the bottom you can use a hormone powder or gell if you want, I use honey you dont have to use anything if you dont want too. Put some potting mix into a pot make sure it is moist poke a hole in the mix with a stick I use the handle of a old wooden spoon, pop it into the hole, I put a empty soft drink bottle over the top put it in the shade somewhere if you live in a warm climate and leave it. With that soft drink bottle over the top of it, it should stay moist and you will not need to water it unless it dries out it should root around 6-8 weeks.. Cheers...Misty