What's your question? Ask

You can propagate them in this manner, but I advise cutting with clean shears, as to not introduce an infection. Most of the time this can be done without applying a protective layer, but yes, you may wax it if you would like. Here is an article on cloning the plumeria: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/growing-plumeria-cuttings.htm

THRIPS!!! Go ahead and burn the house down... Ha ha!

In all seriousness, though, these can be a real problem. They do not respond well to many pesticides, and even seem to thrive once the pesticides destroy the plants further.

There is something that you can do though. I don't like recommending products or brands, but in this case there is something that will be very effective that I use as well.

This stuff is called FoxFarm: Force of Nature Miticide.

Not only does it kill thrips, but most any infestation including fungal and viral. It comes in a ready to use spray, or a concentrate.

Thrips can be beneficial when outdoors, but they have no place indoors or on container plants where they are left unchecked. This article will offer more information: https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-thrips.htm

Those are the seed pods:

https://www.google.com/search?q=plumeria+seed+pod&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi71IewtdXeAhUL4o8KHUWpDkQQ_AUIDigB&biw=1600&bih=783#imgrc=OrNSEEVcnbKxTM:

You can safely reduce by about 25% (2 feet) especially if you can cut back to lateral branches and leave some green foliage. Cutting back to a bare stub will be ugly until spring/summer when it will probably refoliate. But it's safer to leave some green. If you take it down more than that you may get away with it and it will re-foliate in spring but it is more risky for disrupting the physiological balance and creating severe stress.
Water and fertilize to support the changes and regrowth.

This is not strange. It will be ok, but I would let nature take its course. I would not clip the plant until you get ready to put it back out. It will likely survive. Many plants that are meant to be outdoors will struggle when brought indoors. Just be patient and keep care like you would normally. Here is an article for more information on their care: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/growing-plumeria.htm

This can mean several things. Can you include a photo? Usually if the top is completely dried out, then the cutting has likely failed, but a photo will help me to determine that.