I always thought a good Potter spin off would involve George. Maybe 10 or 15 years down the road. He's not the big jokester as the death of his brother had a big effect on him (he's not without humor though). He's an auror, very clever (always was) and hunts down dark wizards who have gone underground and are causing all kinds of chaos. His powers have basically doubled due to Fred's death. He even has something of a psychic connection with him and works out puzzles with his help and even gets premonitions of danger ahead. Harry Potter was something of a Hardy Boys/Nancy Drew sort of thing so why not continue that theme that worked so well? Those 2 were probably my favorite characters and kind of reminded me of me so that's probably why I'd like this direction.
PS When Fred died, his ear healed over the years.