Hi Billie! You have asked a lot in one question! It looks like you will be driving from Connecticut. It's a long drive but it will certainly save you money as you won't have to purchase flights for 13 people. I've never stayed at Orange Lake Resort but I just checked it out online and it looks beautiful. The prices are very good and hotels.com rates it as excellent. You can use the kitchenette for breakfast and dinner and perhaps pack a lunch for the parks. If you'd rather order from a quick service location, most of the food portions are large and can be easily shared - especially among the children.
I'm not aware of ways to save on parking unless you are staying on property or if you happen to be an Annual Passholder. However, if you need tickets, I know many people who use undercovertourist.com. If you haven't already, sign up for the newsletter at mousesavers.com as there is usually a link within that will save you a few dollars on the tickets.
For spending money, you might want to consider purchasing gift cards in advance. If you have a Target card, you can get 5% off. It's not much but it does add up.
And finally,
Baby Care Centers are located in every park. You can find the location of each center within the hyperlink.
I'm just about out of space but I wanted to wish you a very magical vacation! Please let us know if you have follow-up questions.