David that's a lot of questions

but let me try....
Transplanting, cutting of new scions and rooting is best done when the plants break their dormancy, here that is in early spring.
Plumeria are fine in the winter months with no water or heat, they are going to lose their leaves and go dormant.
Not every plant/tip will bloom every year.
The colors are dependent on the varieties that people have brought in. Maybe YOU can be the importer of many varieties of P. rubra into Israel and start a new trend!!!
Many people root cuttings in plastic bags or plastic bottles to be able to see when the first roots emerge, then transplant them. It is not my preferred method, however.