I am playing around with dates and and different scenarios on flight costs for 5 people from JFK, non stop (multi island) the end of june-Jul to Oahu . I have a credit card with 65,000 points and need 42,500 points and $400.00 plus dollars for my fare and I also have a 50% companion pass . Since there is a total of 5 people the rep said that I would need to book mine on a separate reservation and the other 4 separately. I noticed that I cannot reserve it as a multi island as the option goes away

So my question is: what is the best way to structure this and is xtra comfort worth $320 non stop?
My thoughts are that I would have to book my husband and I using the round trip to get the 50 percent companion pass and the 3 kids I would have to book separate one ways in order to use the points . I was hoping that we could book the interisland on the sane ticket so that the flight from Kauai to the mainland the bags could be checked all the way through but this doesn’t seem possible . Am I understanding the rules correctly ? I also could wait to book the interislamd fare anyway and use points from the main purchase and Marriott bonyoy to help pay some of the interisland fare with points .The chat specialist did tell me that I could link the interisland with the mainland fair as long as there is not more than two hours in between. That is an option if that’s correct.

Hawaiian air experts , am I understanding this correctly? Thanks