Well, okay, it's not strictly related to the question... more of a general observation.
But if you were to change a character's personality, the first thing I'd want to know is what's happened since the last time I saw him, to make these changes, rather than just how many years have gone by.
And if I were bringing back a secondary character from an earlier story, I'd have to age them to match L&C -- but I could make them seem a little younger or older, depending on what amount of crap they've had to put up with
Or, if I really needed them to be significantly older or younger, I'd have to give serious consideration to just creating a whole new character.
Unless you want to use "soap opera years" in which babies go to summer camp for a year or two and come back as hunky teenagers
PJ