I would say medium
Easy medium for phone
Apple has more than one person doing coding interviews.
What question?
Depends totally on the interviewer . I was asked leetcode hard but was called onsite when I solved a less hard variant of it . The interviewer was very helpful though . YMMV
Everything at apple is based on the team. For my team the interviews can ask any question they would like
What's the question ?? Do they ask only from leetcode or don't they ask leetcode easy?