Hi Ellsworth! Well, you wouldn't have to give up either one if you ate at
Whispering Canyon Cafe for lunch and
'Ohana for dinner! That sounds like the perfect solution to me, and you could spend the afternoon at the Magic Kingdom between meals! (Although the Skillets are all the rage at Whispering Canyon, the Sauteed Quinoa Cakes on the lunch menu are one of the tastiest dishes I've had at Disney World and they make a perfect light lunch.)
If, however, you must give up one, my recommendation would be to cancel Whispering Canyon and keep 'Ohana. Reservations at 'Ohana are very difficult to come by, especially for a party of 10, so you're really lucky to have gotten a table there. On some trips, I've been unable to make a reservation at 'Ohana because it's so popular. Whispering Canyon, on the other hand, usually has more availability so you'd easily have an opportunity to dine there at another time if you wanted. Both restaurants have good food and fun atmospheres, but in my experience, 'Ohana is consistently more fun. At Whispering Canyon, the amount of fun you'll have depends largely upon your server. Some servers keep you laughing with crazy antics, but on some visits, I've had servers who were so busy they only made half-hearted attempts at humor. At 'Ohana however, you'll always find the limbo, coconut races, and musical parades through the restaurant that make a meal there a fun and festive experience, especially for the children in your party. Both restaurants have good food, but I guarantee no one will leave the family-style meal at 'Ohana hungry!
Hope this helps you decide! Have a wonderful family vacation, and come visit us again at the Moms Panel if you have more questions!