Hi Tammy,
There are two different tea parties that feature character meet and greets:
My Disney Girl's Perfectly Princess Tea Party and the Wonderland Tea Party. The first is hosted by an enchanted rose named Rose Petal and features a visit by Princess Aurora or one of her royal friends. At this tea party children receive an 18-inch My Disney Girl doll as well as other special gifts.
At Wonderland Tea Party, guests decorate cupcakes, sip "tea", and make a craft and play games. This features a visit from Alice and Mad Hatter.
Prices are subject to change, so I recommend calling (407)939-1947 for exact pricing information. The Princess Tea Party runs about $250 for an adult and child. Wonderland Tea Party is for kids only and costs about $45.
I don't know of a tea party that features Mary Poppins and Alice; however, you can meet both of them at 1900 Park Fare for breakfast. The Supercalifragilistic Breakfast is one of my favorite character meals. It features Mary Poppins, Alice, Mad Hatter, Pooh and Tigger - sometimes Eeyore even makes the rounds.
Hope this helps. Have a magical vacation!