I know most people don't agree with me and will end up picking and choosing what they consider canon based on how it can be used in their fic. But since JKR is the only person who can create canon, I think everything she says (even when she contradicts herself) is canon. That said, I personally don't consider 'canon-compliant' short-hand for 'quality' so it doesn't matter to me if something is canon-compliant or not.