If you have the time to be diligent, you might be able to score 2 r/t BF tickets to HNL, but it WILL become your job

As others have mentioned, be flexible. You will have your best luck with mid-week travel. Do not even consider trying to get a free seat on a Sunday night returning to EWR - the First class section is smaller on that flight. I believe the Monday to HNL also has a smaller section. Don't even try around Memorial Day.

Check every day, at least once a day for seats to become available. Eventually they will.

Take whatever dates you can get and waitlist for better dates, as long as they meet the first criteria

IF and only IF you can't get anything on your own and it's about a month out, well, THEN waste 300k miles for 2 confirmed seats. I wouldn't do it now.

Often you can only get 1 seat as an award. Paying for the other one isn't all that bad, nor is using the 150k miles for the 1 seat. The trick is to search by requesting 1 seat, you'll get a better picture of what's available.

Like I said, since the ticket you're looking to get is unrestricted, you can wait to see if you can get it any other way.

While you may have a boatload of miles, it really is wasting them for Hawaii when you could use them to go to Europe.