You may be right about the lack of spread between the front and rear bars, not sure about height clearance for a kayak either. Another member had similar lack of spread concerns for fitment of his rooftop clamshell carrier. The rooftop tracks only extend maybe 3/4 towards the front of the vehicle and the track looks like it won't allow the rear bar to slide completely to the rear (photo below).
Thread link below for other crossbar debate and the mounting instructions/diagrams from MOPAR. It does look like these cross bars are more robust than they appear and have locking mechanisms. One of the forum members was going to take a photo of the mounting.
I'll have my rig and the mopar crossbars in hand in two weeks and can report back. Even if they do look solid (Thule is provider), I'll still check if aftermarket alternative is any better.