Interesting, as I did not realize that DL and HA did not have an official interline bag agreement, despite having the ability to sell tickets on each other's flights. The actual list in the link provided above was much smaller than I expected and I see some airlines missing that I know DL can interline with, but they must be by exception and not policy.

Anyway, I think this solidifies to OP that they shouldn't bank on DL checking bags all the way through, and that if they do choose to book separate tickets, allow plenty of time between the two to take care of bags and have padding in case of delays. Or, even better would be to rebook all on one ticket, either by taking advantage of a schedule change entitlement or cancelling and using the resulting credit.

On the rare times I have to fly two different airlines and have separate tickets, I always allow at least 12-24 hours between flights. For Hawaii that's probably overkill, and I usually only do it when connecting on an international trip that has lots of moving parts and want to minimize the chance of any hiccups.