Menus posted on the Internet are guides only. Even at the Official Disney site. You will only KNOW what is available when you sit down. Most Disney restaurants do not have extremelly extensive menus. You need to be sure that you are happy with that before you buy the DDP.
'OHana and Kona are totally different experiences. We like both 'OHana is a larger, noisier restaurant that has entertainment for young ones, as well as all you care to eat skewars of meats and sides. Many love it, many hate it, and you will find lots of both opinions here on the DIS.
Kona is a more traditional table service restaurant, albeit with a somewhat limited menu. You will order your entree and desert and be served at your table. There is nothing special happening for the young folks.
With over 100 restaurants participating in the DDP, you have lots of options. Check the various sites mentioned by PP to see what most appeals to you.