Honestly, I would say no to have to pay for 5 adults for only one 2 year old to see Mickey...Mickey is relatively easy to see at WDW.
We took my son who was turning 3 on the trip. It was a wonderful memory for us to see him with Mickey BUT he doesn't remember it (he is 6 now), and I could have got the picture and experience for myself with the price of park admission vs. paying for that dinner.