for GJ,
teenage : River Phoenix
young : Eric Bana
middle age : Mel Gibson
old age : Sean Connery

for HR,
teenage : Natalie Portman
young : Jennifer Aniston
middle age : Annete Bening
old age : Julie Andrews

for YG,
young : Brad Pitt
middle age : older Brad Pitt

for LHC,
young : Mark Wahlberg

for WXB,
the actor that played Cody Banks.

for XF,
pretty much the same as GJ except we don't get to see him as teenage and old guy.

for XLN,
Liv Tyler all the time.