I agree with those who say sit it out and then solve it after the fact with customer service.

There's at least one thing Delta did wrong here, because I've personally flown an award ticket OGG-HNL-Elsewhere where the first segment was on HA. I specifically overpaid in miles for the first segment vs a cash ticket because I wanted to be protected for the connection onward on a once-every-two-days internstional itinerary. The miles price is always additive with HA (e.g. you have to pay for those segments as if they are separately ticketed which drives up the price), but they can be ticketed on the same ticket at least.

Also, F is all kinds of nothing special on these interisland flights. The 717 is basically a glorified regional jet for HA and the flight is a 25 minute sightseeing jaunt; you will literally spend more time boarding than flying. Given that the miles prices are always additive, I would actually prefer to book coach for these segments - that's certainly the route I took for my honeymoon flights, even though we were connecting onward in KE business.

Wife didn't mind a bit for the short segment. (But to be fair, she is also diamond, so she would have been madder if I overpaid in miles for the itinerary than if she wasn't up front )

I'm sure you'll get a refund of the mileage fare difference and some apology miles for the inconvenience, once you reach out to DL customer care...