Don't have any official knowledge but based on booking lots of HA flights (mainly inter island) they tend to block several rows of seats, especially the ones immediately behind first class for special needs (medical, unaccompanied minors, extra assistance) passengers.

They also book for tour groups. These seats may open up close in.

I have minor status on Hawaiian and am usually able to get moved up when checking in--it's up the agents. Ask quietly and nicely. Good luck!