I found that a big meal before the party (and Ohana is a BIG meal) really slows us down. We don't want to do as much because we are so full it takes a while for us to get into the swing of things.
What works for us is a table service lunch around 1:30 - 2:00 then hit the park at 4pm (with our party ticket), see those attractions that are not open during the party, and then at 7pm we start with the party stuff.
When we're hungry we just have counter service or snacks.