>when you see it
As soon as the kids are free the battle is potentially over. In a nasty way. Our top priority is to free the kids as fast as possible and unfortunately I can't do much about chains. I need Cat.

My plan:
Cat uses feline agility + rush = 4x movement speed = 120 (yes, that stacks and can be stacked even further with spells) to get to the rear of the cart but she won't have an action left to do anything. When she passes by me, Yulya casts emboldening bond on both of us. I should be exactly 30ft away from her and still within range. I follow Cat using stealth and have an action to see what I can do with the chain.

Meanwhile Ashley has to distract them for another round, good luck!

Next turn Cat can use hammer and piton or the crowbar with her enormous strength in combination with emboldening bond rolls to detach the chain from the cart.
When we free the kids we give the signal, Yulya tells the horses to go to get the cart out of the way and the wasps sting the rothés in the right side of the noses. they charge to the left trying to make a u-turn, the cart abruptly turns left and the rear of the cart will crush those two fools against the rock before them. Ashley panther and summons will have to deal with survivors until Cat and me arrive but I don't think there will be much resistance after being ground to a pulp.

It's still a huge gamble but with the cart as a weapon it sounds far more feasible. Plus we technically didn't attack or kill anyone, it was a tragic accident. Shit happens.