So, it seems as though McCree can only see if Mondai is touching him? That would explain why he could read the book, right? And "being his eyes" as his only job... I've noticed that when he has Mondai, his eyes are green. But when Mondai flies over to Hanzo is when his eyes went gray... Am I onto something at all?
(This is the weirdest post I´ve ever made.)
First things first: Mondai does not have to touch Mccree. Mccree sees the world through Mondais eyes 24/7 but if he is flying around playing with Hanzo he can also only see Hanzo and so he walked against the tree.
To answer your second question honestly…. sometime I am lazy… and I forget to color the eyes brown… so they get grey sometimes but that actually is not connected to Mondai. There is this one time they got a little greenish… *tries to look normal but is definitley hiding something* THEY ARE TOTALLY RANDOM TOO.