I see this got a little contentious, but before I even read the other posts, I too was going to ask, "Why Hawaii?" If it has to be Hawaii, cool. But it's worth poking around in your brain (and the brains of the other travelers) to see if there is a cheaper and/or easier way to scratch the same itch.
I've been to Hawaii. We stopped there in the middle of a move from Japan back to the US. We spent some time in Honolulu an went on a cruise that hit up several of the islands. It was very nice. But... just very nice. I've done a fair amount of travel, thanks in large part to living overseas. Hawaii isn't on my top 10, probably not even top 20. I've been to prettier beaches, I've been to more charming little towns. There was nothing about Hawaii that seemed best-in-class, whatever class it might be, for me. Now, everyones values are different. And for some people, just the idea of Hawaii has a mystique that calls to them. (Fantastic PR, Hawaii!) But even then, I think you need to ask whether "mystique" is worth paying 30+% more than you could for a very similar trip elsewhere.
So many people thin Hawaii is a unique, special, magical place. Because of that, I expected it to be those things and I was very let down. It makes me wonder how many places those people have been. (Gawd, I know how snobby that sounds, but it really was the question I asked myself. Like, of course this is magical if it's one of the only places you've visited outside the one you live. But if you've seen many places, is it still magical? it definitely wasn't for me.) I had moderately high, but not exceedingly high, expectations and it definitely fell short for me. But some people like mushrooms and I think they are disgusting, so... everyone is different.
Yes, nothing else is Hawaii, just like nothing else is exactly like anything else. That's why it is key to determine what exactly is the draw for Hawaii. If it is bragging rights, then yes, nothing else will let you say, 'we went to Hawaii'. But even then, maybe it s equl or better to brag that you went to Iceland or New Zealand or Rome. If it is the beaches, there are gorgeous beaches around the world, and many of them have much cheaper labor and therefore overall lower costs and would be less expensive to get to, especially from the east coast (and might eat up less of your vacation with travel time). Whatever the draw or draws, there may be a great substitution (and there may not be), but you won't know until you zero in on what is pulling you toward Hawaii.
Where that "elsewhere" might be depends on what you want to get out of the trip. And you are late enough in planning that you aren't going to get the best deals to just about anywhere. But you might find a great substitute that gives you most of (or even more of) what you are looking for in Hawaii, for less.
That said, you might also compare the price of that cruise I mentioned. It goes in and out of Honolulu. You get to see a little bit of several islands. There are also cruises that leave from LA, I think, so you wouldn't need to pay to fly to Hawaii, although then you couldn't add additional days in Hawaii. It might be cheaper to eat and drink and sleep on a ship than on a Hawaiian island, and would let you check the "Hawaii" box if that's important to you and your family.
If I had a large block of time and a fair amount of money to spend in summer, I'd go to New Zealand (which is trendy and has similar bragging rights as Hawaii, though it would be winter thee) or I'd rent a car and hop around Scotland. The prettiest beach I've ever been to was probably in Turks and Caicos. Or maybe I'd hit up Europe, and go to 2-3 cities (or more, if you stay more than a week), and that would get you some beach time, some culture, and a "bucket-list, bragging" type city like London or Paris or Venice.
