Been to Ohana for dinner twice - 2009 and 2010. It is NOT worth the hype it gets. (link below for my review). We had a great dinner in 2009 but in 2010 we had a very frustrating time checking in and waited an hour to be seated. And the food was not out of this world or anything like that.
If you do go, here's a few tips.. Arrive EARLY, VERY EARLY, to check in. The check-in process can be a long wait... just to get a pager. I saw the line to checkin going all the way back to the monorail entrance. I waited 20 minutes to check in, then another hour to be seated....with a 5:10pm ADR. If you have an ADR shortly after 5pm (Ohana opens at 5), I'd arrive 4:40pm. You might get there and have no problem and be seated right away.... from the reviews I've read, it just depends.
While waiting, grab yourself a drink and check out the gift shop, take some photos, etc.. I'd really like to know how far I could go with one of the pages and still have it work (could I walk to the beach?)
Wishes Fireworks - I would not want to watch this from the restaurant. I can't imagine the view, if any, being good. You are much better NOT being in the restaurant during Wishes and walking a few feet outside to the beach by the Volcano Pool. The electric lighted boat parade also passes by a few minutes after 9pm.
Go to the 1st floor resort registration desk. Ask for Leis - they have fabric leis (no charge). Ask for a resort activities schedule and when the welcome the night ceremony is. On most nights (I think nights when they have the Spirit of Aloha show), performers from the show do a short (10 min?) ceremony just outside the main building around 6pm - drumming, fire juggling, lighting the tiki torches.
While there, if you haven't been to the Grand Floridian, I'd visit their lobby. In the late afternoon and evening, there's a piano player and small orchestra that play. The lobby is beautiful and some neat floor tile work with characters.
Have a great Trip!