Hi and welcome!

I’m not in Hawaii, but can offer some suggestions that I’ve gotten from other’s posts in the past. I guess you have quite a good amount of native insects. Some have suggested catching wild grasshoppers and roaches and starting to breed them. I see that Surinam roaches are native there. Those are quick to breed and are smaller sized. They are fast and very good climbers, so you’ll need a bin with a gasket lid and smear something like Vaseline a couple of inches before the top to keep them contained. They like to burrow in soil so it’s best to give them a couple of inches of soil substrate. Here’s a bit of info on them.
https://www.roachcrossing.com/for-sale/roach/all/surinam-roach/
I don’t know how to breed grasshoppers, but other members can probably help you out with that.
@SauceGandhi breeds/sells grasshoppers and maybe can offer you basic instruction.
From previous posts, you can probably obtain silkworms or their eggs. Some mentioned Petland Kahala, but those posts were over a decade old. Since silkworms basically can’t survive/reproduce without human intervention, they should be legal.
If you can find some hornworms in someone’s garden, you can let them mature into chrysalis - hawk moths and then breed your own hornworms. Unfortunately the wild diet of hornworms makes them toxic and is why you can only breed them and not feed them off as is.
Even if all of these feeders were as available to you as a trip to a pet store, it does get expensive feeding 3 little hungry mouths. Breeding your own feeders - even crickets - is a great way to keep costs down and brings a strange satisfaction that’s kind of fun and interesting. The how to’s are readily available all over - I like YouTubes how to’s.