1. Best, maybe Dead Poet's Society, worst, probably A Wrinkle in Time (read the book y'all, it's actually worth your time.)
2. It's alright for a white noise show, not much else.
3. It depends. Raven would be the smartest. Starfire would have more challenges with communication not necessarily dumb. Cyborg is alright, no dumber than most of society. I'd say it would boil down to Robin or Beast Boy. Mostly because Robin might be wise, but the boy needs to get his dang life together before he worries about others. Beast Boy is satisfied with his life, though has a lower IQ. The dumbest of the two simply depends on how you rank intelligence, either by academics or by overall life.