It isn't said how they meet they just met I guess. It is unknown so we just imagine how they met. There is no right or wrong answer. they meet in a jail cage inside of the twilight realm.
Links height varies in many of the games he stars in, plus his age changes from kid form to adult from.In the game Super Smash bros brawl Link stands at around 5'11,In Zelda and the Ocarina of Time...
Probably not (if you noticed midna shattered the mirror of twilight, the only thing connecting the twilight realm to hyrule, in the cutscene after the credits of twilight princess), unless Myamoto...