Hello Friend!
Welcome to planDisney! I saw your question and wanted to help plan your fabulous upcoming Walt Disney World Resort trip! Celebrating birthdays is always magical in Walt Disney World and being there with little ones is just so special.
If I were to suggest two Parks for you to visit with your little ones I would suggest
Magic Kingdom Park and
Disney's Animal Kingdom Theme Park. Magic Kingdom Park is already my favorite Park as it has the most rides with no height restrictions. You can carry your baby and sit next to your 2-year-old on quite a few attractions as they are gentle but still so much fun. Some family favorites with little ones are Dumbo the Flying Elephant and The Many Adventures of Winnie the Pooh. There are a lot of things to do in this Park and to be honest I could spend two full days in this Park without repeating an activity.
As for Disney's Animal Kingdom Theme Park, there are so many animal exhibits and even a petting zoo. I suggest taking the
Wildlife Express Train to Rafiki's Planet Watch. It's a hidden oasis with an
Affection Section where you can make some furry friends. I feel like this Park is much more relaxed with a lot more emphasis on exploration and learning. It is a great contrast to the noise and color of Magic Kingdom Park.
Lightning Lane Multi Pass and Single Pass can be purchased on the
My Disney Experience Mobile App only. If you are staying at a Walt Disney World Resort Hotel you can make your purchase at 7 am, 7 days before you arrive. If you are not staying at an eligible Resort then you can purchase it 3 days before. At the time of purchase, you can make three Lightning Lane selections for the Park you choose so that when you arrive you have three attractions ready to be enjoyed with minimal wait. Don't forget that once you start using a Lightning Lane you can book another. You can continue to book attractions as you use them throughout the day and until they run out.
I hope this helps and you have a fabulous time!
Happy Planning!
-Nimmy