When players are lined up at the free throw spaces, where can their feet be? Can they be touching the lines that divide the 4 spaces on each side of the lane? Can they touch the block at all? How far back from the lane can they stand without causing a violation? I know that players outside of these spaces have to be behind the free throw line extended and the 3 point line, but I don't know the restrictions for the players who are lined up. Anyone know the NF rules for this one?

Re free throw
 

NF rule states they must be within the marked spaces and cannot stand on the blocks.

Within means neither foot can be "over" either the lane line or block. The arm(s) can but not the feet.

To answer your question of how far back from the lane the players can stand, look at 1-5-2. It states that the area is 3 feet back.