Definitely not Brunfelsia. Brunfelsia has alternate leaves and Pomegranate are opposite. Plus Pomegranate has angled twigs, different leaf shape and size and different veination pattern. These all support the first identification. I think the reason you are confused is due to that fact that juvenile plants have slightly different leaf morphology (larger leaves) than mature specimens (as the one you provide)..

Ohhh I see Malaysia is a bit different from me When #4 was in flowering for me Sun time here at longest is about 15.75 hours buds where easy to see and nearly ready to open and did so with lesser sun light time and finished flowering 12 days later. Temps where in the 80 - 92 F range at the same sun times mentioned and the time of day mine opened was 16:00 hours to 23:00 hours For now I can say your heaviest rain season might be a bit much for #4 although the soil you have it in does look nice enough to drain fast enough. Again odd #4 Messeb like water more than most succulents but doesn't like wet roots for to long of time in days the top will rot out on you if to wet to long. Your other plants would certainly benefit with a lot less water than #4 can handle Other than a season rain over watering concern I have think you'll do very well with yours. As caution I think it would be best if you could provide a tarp or tent for some over head covering during your heavy tropical rain season over the entire garden bed. I and others here appreciate you and want to see your plants in there best of flowering later too. In all honesty it's best to tell you to talk to some of your local people with the same succulent garden passion as yours and ask them what they do.

That is the scariest thing I've seen since the movie "Aliens" LOL! I didn't even know cosmos HAD tubers. But from looking I think you're right on circling the yellow parts as what would produce upward growth. My guess on the purple circled roots are a younger set of roots. My guess on the red circled part is an older root. And the green circled clump: my guess would be the original little clump that has gone on to reproduce the red and purple circled parts. Lots of good looking white roots in there too, so they must be healthy. I would guess you could separate this mass into at least 3 plants, but like I said, don't know anything about cosmos tubers. Can you inquire at the bulbs forum here?

I just saw the leaf furthest to the right in the last pic - definitely HVX. :( So sorry - it's so lovely otherwise - that stinks!