We'll be taking my 3yr old and (almost) 9 month to Six Flags soon with their cousins. The weather is weird here and I don't know if it'll be a perfect 70F or scorching 85F.

Obviously sunscreen and hats. I plan to bring our Beco, stroller and Radio flyer wagon. There will be 3 of them age 3, 6 & 8 so I'm sure one will be tired at some point. And if not it'll be useful to hold all our stuff plus a cooler bag with ice cold drinks and snacks? Or would the wagon be a hinderance to bring along with the stroller?
I was thinking about pre buying the bottle fan misters for the 3 girls? I know they're super expensive at theme parks!

I am a tad concerned if it's a really hot day how my baby will do. She seems to get overheated really easy!

There will be 6 adults.

Any other tips?