Hi, I just stumbled upon your post. We use these flowers a lot in our island. People make offerings (to god and ancestors) with these flowers. In our language it is called "Nusa Indah" which means beautiful island.
The one that familiar to me is the pink one such as the one in your photo, and there is also the one in white color. We use them both.

And reading @ydraz comment, I just knew its latin name. Thanks.