I would take it inside and place it under a grow light. Since they are new cuttings, it won't hurt them to grow them through the dormancy season and continue growing during next grow season. Keep them inside all winter under grow lights and let them bloom. Then, bring them back out when your other plumerias start growing leaves outside. It will need lots of food while it is blooming. Treat it the same as if it is outdoors. You might want to consider getting a heat mat, depending on how cool your home is and how much heat radiates off the grow lights.
