Some take years & years before they bloom. That being said, how many hours of direct sunlight does it get? Also, what's your fertility program like?

I only fertilize my big one. About every 2 weeks. Maybe once a week if it's producing inflows... With that being said, I'm scared to fertilize my other ones(you can see some in the pic along with the Hilo). Should I start fertilizing the Hilo beauty? Or should I only fertilize plumerias if they have inflows? Also it gets direct sunlight.

Plants need food all the time, not just when they have flowers.

Where do you live? My Hilo is a somewhat shy bloomer and makes very long internodes before it blooms. Yours may bloom next year or maybe late into this season.