For the record, I am not against children (else we wouldn't have had four of them )

It's been a long time since we traveled with infants, but I do recall the extreme hassle and crankiness associated with even a simple midcon flight.

As a Hawaii resident, I can tell you that I see all the time parents and infants in the airports, looking stressed out, sniping at each other, tired, and schlepping those Humvee-sized baby strollers. When you add in the overnight time zone change, and consider the possibility of irregular ops (do you want to have to be dealing with figuring out whether to sit at the airport for 12 hours or find a hotel if you flight is cancelled/delayed?) I'd say leave the the baby with the grandparents.

If this is a trip you've looked forward to, use it instead as an occasion for some R&R time as a couple. If you find you love Hawaii and want to come back, bring the child when he's 10 or 12 and will be able to enjoy it and remember it.

Fwiw