Hiya Mercedes!
Welcome to planDisney! You are going to be right in the not-so-spooky magic very soon and boy am I excited for you! Your little ones will have a fabulous time at
Mickey's Not-So-Scary Halloween Party! Make sure they have a nap and a good dinner in them before all of the fun and candy. Trust me, it will be needed!
Since it will be a long evening I see the need to bring a really good stroller for your little ones. Unfortunately,
Walt Disney World Resort Property Rules state that stroller wagons are prohibited no matter the size. Also, bicycles are not allowed in the Parks. If the Swing Stroller Tricycle Push Bike looks like a bicycle then there is a good chance security will not let it inside the Parks. There is a slight possibility that if the pedals are removed or made into a stationary foot stand it could be allowed but if there is a way to have it modified easily by a guest it may not fly. In the end, security will make the call but I would hate for you to travel to the Parks with excited kids only to have your stroller of choice rejected.
My suggestion is to find a traditional stroller that reclines for your little ones. It will be a long evening and that recline would be a real comfort for them. It must fit the size required of being less than 31" in width and 52" in length. When my kids were little I brought a stroller they were familiar with from home and now that they are a little bigger and don't nap I'm fine with just
renting from Walt Disney World. The strollers from Walt Disney World don't recline and have to be returned before you leave the Parks at the end of the night. They are perfect for Park strolling but your little ones will most likely need something different.
I hope this helps and that you have a fabulous time. Happy Planning!
-Nimmy