If I have several scripts, how do I make sure they execute in sequential order?

i think you can set a priority on the scripts with a comment at the top, like so:

script 1

// priority: 0

/* your code here */

script 2

// priority: 1

/* your code here */

I'm not sure if this actually works, I just am assuming it does because the default scripts that ship with KubeJS have these priority comments in them

What HipHopHuman said is correct, otherwise if no priorities are defined the order by default should be A-Z