We were in Honolulu only 2 nights but thought I'd share our experiences:
Side Street Inn - on Kapahulu - We met our local relatives here and we were a party of 15 people. My cousin made reservations and preordered for us. We had fried rice (with the Chinese sausage), edamame with garlic, ribeye steak, ahi with furikake, pork chops, ahi with pesto, and Chinese chicken salad. Everythings was so good. My favorites were the fried rice and the ahi with furikake. Loved all the greens served on the side of the entrees. My CA cousins loved the pork chops and the ahi with pesto. We ordered multiples of everything, way too much food. Fried rice reheated nicely. We will definitely return on our next trip.
Hawaiian BBQ - Ko'Olina - Great prices for decent food. DH and I shared kalbi ribs. DS1 enjoyed his burger, and DS2 had teriyaki beef. Cousins had a mixed plate and a fish. Everyone was happy. Would return if we're in the area.
Waiola shave ice - love this place. Went each day, including 9AM on the day we left. Wanted to also try Ailana's but just couldn't get over there while they were open.
7-11 - The people who rented us their condo suggested that we pick up spam musubi there. We got some for the plane ride home - really good. Also bought some manapua, but they were dry. DH had a breakfast burrito with Portuguese sauge, he enjoyed it.
It's been a few years since we visited the older location. It has a grittier feel - a little darker, more like a bar. The Kapahulu location is plusher and shinier. I kind of prefer the old location - just felt more homey and old school to me. Consider taking more people than your SO. All the food is served family style and there's a lot of it. Enjoy!