When a year is required, many poskim hold that a 13 month leap year is considered a 12 month year.
Chew on this:
The Bar Mitzva boy does not become 13 years of age, a Gadol, a few months earlier because during the 13 years there were 3 leap years.
Logically, he should become bar mitzva at least a month earlier than the boy that only went through 2 leap years in his 13 years.
The same applies to all the other questions. Logic does NOT conform to halacha.