What are your other ADRs? What does your family really enjoy? By that I mean, is your family really into quality, delicious food? If yes, I would absolutely skip O'hana, as there are many other restaurants that can deliver at a fraction, or at least less than the cost of O'hana. If your family is really into the theme or the atmosphere, O'hana might fit the bill, depending on what you like, BUT in my opinion, other places execute much better. You just have to decide what factors really drive your family to have a good meal, and go from there. We visited O'hana last August, primarily because I felt that a lot of people were saying how much they loved it, the reservation was hard to get, and I love the Poly. It did not live up to our expectations in the least. Our reservations were for 440 pm and we waited at least 20 minutes beyond that. It was really chaotic and loud. Our server was meh and the food was meh. I think someone mentioned a local Asian restaurant may be better, and I can concur with this statement. There were coconut races and a ukulele player. Someone was on a microphone. My kids were not interested in the coconut races and their heads were live swivels on sticks, watching all of the action....and not eating. It was one and done for us as well.
BUT, I would never ever tell someone not to go to a restaurant based on our experience, as your expectations may be different. We had much better meals at the Wave, California Grill, and from kiosks throughout Epcot. That is also how we roll though...quieter, understated eating atmosphere.
I also want to touch on one more thing because I can almost feel it in your post. Please do not put too much pressure on yourself to make everything perfect. That will undoubtedly stress you out and the perfect moments often come in the imperfect circumstances. I can relate to wanting to ensure that everyone has an amazing time, especially at the Disney price tag. Just make sure to enjoy just being together and if the food stinks somewhere, lament together, try to joke about it, and carry on. One of our absolute worst meals was at BOG and even today we have to laugh over the wilting lettuce, my kids playing with their droopy fries, and my daughter legit freaking out at the thunder in the rose room....oh and some guy refilling his water bottle at the guest water jug...you know, putting the lip of where he drinks on the tap of where the water comes out for everyone else. Memories...good times. Have an absolutely wonderful trip!