I transplanted my Royal Poinciana seedlings about two weeks ago. There was no new growth for about a week as the plants put out adventurous new roots. I didn't see any signs of shock and there was no leaf drop whatsoever. Then about a week ago they started putting out new and even larger leaves. I'm a huge fan of large leaved plants, and these compound leaves make the plants look even more elegant.
I have no idea if I'll ever see flowers from these plants. In my opinion, the foliage alone is a good enough reason to grow them. I've been in contact with a local hotel with a glass atrium that is interesting in taking a few of the seedlings. I'll keep some for myself and try to donate others to greenhouses and garden centres. If you'd like to swap a plant (and are reasonably close in Ontario) just let me know!
If you ever plan on growing Poinciana for indoors I would recommend choosing "Dwarf Poiciana". It's actually a completely different species but more shrub like and therefore manageable indoors.