Hiya Maria! Welcome to planDisney.
Our youngest bunch is 21 months apart and includes our daughter and identical twin brothers. We are finally in full tween mode in our house, but there were years where I essentially had triplets! So I completely understand the desire to bring something into the parks that can hold ALL THE THINGS!
That being said,
wagon strollers are on Disney's
restricted list of items, and there isn't a way to get approved for them. You are more than welcome to bring a single or double stroller, as long as it is one that you can push in front of you, and it is not larger than 31" by 52". There are also strollers available
for rent at the resort (super convenient, because you don't have to bring one from home!). The rental spot is right outside Disneyland Park, to the right of the main entrance gate.
If you need to carry
medical equipment into the park or bring an ECV or wheelchair with you, they need to be single-riders with at least three wheels and must be manually or electrically powered. Mobility devices (ECVs and manual wheelchairs) are also available
to rent at the same place as stroller rentals. The rentals are by day, and you can use them in both the parks and Downtown Disney.
Maria, if any of the littles need a break during the day, the
Baby Care Centers are fantastic! They were my favorite place when we brought our shortstacks to the parks. You have an air-conditioned place to feed, change diapers, pump, and relax before heading back to adventure.
I hope this helps. You know where to find us with any other questions. I hope you have a magical visit!
Rayna