I don't know the character you two are talking about, so I have no opinion on the type specifically, but cloud - do you really think Js don't break rules? That Js can't bring about change? That they always follow a literal schedule? That they're incapable of operating outside of, or to undermine, existing systems?
Because that's kind of ridiculous. If you think all of that about Js, then you probably should think Ps can't have plans in their heads. The truth is, people are almost never that extreme - in either direction.
In general: is the character someone who prefers to think things through ahead of time and to prepare for contingencies? Someone who works best when they have some degree of structure, perhaps self-imposed, in which to operate? Or, are they someone who basically prefers not to plan so as to leave room for spontaneously following opportunities as they arise, and who works best when there's no structure at all? Are they more inclined to alter the external world in accordance with an internal model, or to adapt their own behaviour to the environment in which they find themselves?