Kadie, since you are in a tropical area, there is no rush to move that plumeria, and thus, I would wait for dormancy. I have never left my plumeria in the ground for longer than 7 months, so when I had to move them inside, there was not an extremely large amount of long roots. I just dug down and as wide as was reasonable, cutting through some roots for sure, and thus could easily lift the plumeria out. Since those roots would have no water for five months, and would be complete desiccated, losing some roots was no big thing. You are in a much better situation than I, since you leave your plants out year 'round. Those roots that are lost should not impact the growth/health of that Celadine. Celadine are very tough plants. Your dormancy period is probably much less severe and much shorter than what I deal with.