The man in the car

I think they really liked him and just reused him as a different character. Because, I can tell you that the towns in COTC 5 and COTC 6 are different. COTC 5 takes place in a town called Divinity Falls, while COTC 6 goes back to the first film's original town, Gatlin. Also, to my knowledge it never mentions the man's name in COTC 5 but we know that in COTC 6 his name is Jeremiah Johnson. I would assume they got him to play different characters because Jeremiah mentions that he was born in Gatlin and that that's where he's from. So like most he would never leave his home. Which leads me to think that he would never move to Divinity Falls. And also Jeremiah is a child of the children or perhaps an orginal follower himself which would mean that he would know who HWWBTR is and he would not have called him "He Who Walks Beyond the Clouds" in COTC 5. He would also not have called the children "what a nutty bunch of fruitcakes." because he would have been one himself. Because we know that he helps start revealing to Hannah the prophecy. Hope that makes sense and helps.

"A CHILD SHALL LEAD THEM"