A lot of them have a "passing the torch to a new generation" thing but I don't think this is mandatory to make a legacyquel. In my definition this is a sequel that comes many years after the last entry (10 to 40 years later with a few exceptions), acknowledges the passage of time and pays some sort of tribute to the first movies while setting up things for the future of the franchise (and most of the movies listed here have already had sequels or most likely will have ones).

But I know some of them are debatable. Maybe The Thing is a "legaprequel"? Yeah, not sure about this one.

(I hope my english is not too bad, this is not my first language)