You could ask these nice people: http://www.bovees.com/ Who are the US authorities on vireyas, apparently, However I would also try some Australian gardening forums if you can find them; specifically ones for people in Caires, Darwin and other truely tropical parts. The collusion between Commonwealth culture and tropical climate could well mean they are particularly inclined to growing such plants if they exist; even in mild, oceanic Sydney the vireyas are used as garden subjects so I think, overall, they probably have more expertise with them as a country than anyone in the US. Or even a Florida gardening forum though I suppose it's only Miami and south where conditions are similar to yours. Obviously the various standard southern indicas and southern native Azaleas grow around northern to central Florida but I don't know what their southern limit is. For example, I found this in google: http://www.camelliaglen.com.au/

" . . .and I did not expect it to grow so fast" With any new plant type as soon as it sprouts; begin reading, and read as much as you can. I've found that brig/datura height is relative to container size; they have a very vigorous root system; take heavy feeding and can be abused a bit. As stated above, it might drop a bloom, but I've not had any real transplant shock.

I would bring it back to the nursery and get a healthier one

Im growing Avacados and Mangos in Florida in the ground. We are in So. Florida. Trees are 1 1/2 yrs old and have tripled in size. They are planted in pure sand. No mulch, no nothing. We hardly water them because we do not have sprinklers and only use water for the flowers. Being new to these trees, my guess is they like to grow roots in a very well drained media (sand). They go dry for months on end. Of course, in a container, your can't let they dry out like Florida. I would repot in Spring. Get them out of coco fibre and plant in something that drains quickly. You could use a potting soil and mix a bag of perlite into it so you get good drainage. That's the easy way I would probably take. You could also mix some pine bark into MG potting mix (or whatever you like) and add perlite to that. My trees are growing in full Florida sun. These trees need strong light. Good luck, Jane