Charleen, that is certainly an option. The size it is, it will need more growing space (read: bigger pot). Just remember, if you take off the tip you will sacrifice blooms for the year.
Both of you ladies are growing plumeria outside of their 'comfort zone' and so will have to work a little harder to get them to thrive and bloom! The key is a very well draining mix, possibly extra light hours and fertilization.
