I like the way you observe that the Ronso's resistance to Yuna's pilgrimage seems like so much more of a betrayal because of Kimahri's loyalty and steadfastness. I think that is a very accurate estimation of why it is so unexpected.
I really enjoy the idea of the natural cave as the Ronso guest house and the concept of history portrayed in the many names carved into its walls.
I like the idea of a Final Aeon being less powerful when it's not used against Sin, that seems like an interesting explanation for how Seymour can be using his Final Aeon for ordinary fiends without destroying himself.
I also enjoy the thought that Kimahri helps Lulu to find the hot spring, since he seems able to tell she needs a bit of a break from the rigours of the pilgrimage.
This was an interesting chapter for being calm and a break in the heated action. I think it works well that way.