Almost universally BAD casting
I've read all of the books so far with my kids...
If the books weren't illustrated, I could see how they could take such liberties, but they are illustrated! Based on the style of the drawings, Greg Hefley is a blond kid. His mom is a brunette. The Coach has a bristle cut, like ex-military. Roderick looks like he's a sophomore high school, not college. And so on. There are two supporting characters that are even close to the book: Chirag and Fregley.
What they've made looks funny, but I don't get why anyone would adapt a book like this and intentionally take such liberties and make such blunders.
What were they thinking?