Just so you know, I have never had a problem asking for an extra plate for the child under 3. I was never charged at sit downs for him. And at some point, each of our 3 boys were between the ages of 6 months-3 yrs when we were sharing with them. Best bets are to stick to all you can each, family style like Liberty Tree Tavern, we love this place. We are definately doing the dining plan when we go in September, since between 2 counter service meals for the older boys, there will be plenty of food for the younger one, in fact they might all be able to eat off of just one counter service, and save the other one for dinner, then use the dinner towards a signature for us adults. But not sure yet, if we can do this, come september they may have worked the kinks out and it may not be an option.
The pack n plays for the little ones is small, in fact this is one of the reasons why we will do POR, for the trundle bed, because our almost 3 yr old will not be able to sleep in a pack n play, and I really don't want him in our bed. The values are great though, we love ALL Star Movies! But we have never stayed at POR, so it will be a new experience for us.
The baby will be able to ride all the rides in Fantasyland, with an adult, like Peter Pan, Dumbo, etc.
For our 3 boys 7, 5 and almost 3 at time of travel, I will rent a double stroller, the oldest will either walk the entire time, or hop in by their feet, all the boys are light weights! Have fun.