When sleeping in a diner for resting you see now before the sleep animation some conversations scenes between those 3 characters. Where they talk about the past what happened on their journey and some small talk. The further you are in gameplay the more they talk about it in those scenes. when you do it like me and power up some spells by sleeping 40 nights at begin in a diner then there is a point where they dont talk anymore till you get further in the story.