a Qualifier is a player who couldnt get into maindraw cos his rank was too low and WON his qualifying matches
a LL means a Lucky Loser (the highest ranked losers in final rd of qualifying get into maindraw if someone pulls out of maindraw---but they have to SIGN in as a LL.
a WC is given by tournament directors to:-
someone who they think will either attract more fans to the tourn
someone on a comeback trail after injury cos/and his rank is too low
but more are given to local players of the same country.
I'm sure someone will have a better explanation than me in clearer English