Q.plumeria
my wife and i live in albuquerque new mexico and 3 years ago our daughter, who lives in florida brought us 4 “stalks” to plant. we put them all in one pot and were able to bring them in the house when it got 45 degrees at night and during the winter, leaving them in the sun most of the day and all night during the rest of the year,outside. last year we had several blooms, this year we have blooms on all 4 stalks. they are all about 4ft. high and point in 4 different directions. i transplanted them into a pot about 16in wide and they are spread to a canopy about 5ft wide. iwont be able to get them in the house when cold comes. there are seed pods now (2) what can i do to keep them healthy & happy when winter comes. can get below 20degrees in winter. should i transplant separatly? how? thanks, warren

This tropical shrub probably won't survive down to those temperatures, at least for very long. If there are four separate shrubs, you may transplant them out into some soil, with maybe a little added. Carefully pull all of the roots apart from each other, and Give them each a separate pot.
Also, Pruning them can help with shape quite a bit, which may allow you to bring them inside. Here is an article on how to correctly prune them: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/plumeria-pruning-info.htm
And here is an article on their care: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/growing-plumeria.htm
And last, about the seeds, it never hurts to try and germinate them. Try them in soil, or the method that I prefer. It seems rudimentary, but it works almost every time for me. Take them and place them in between a MOIST paper towel. It should not be dripping. Put them in a bag, and place them in a drawer, checking them every day to see if they root.