There are two separate requirements:
1) A player aligned stationary and at most a yard from the LOS at the snap may leap from beyond, within or behind the NZ and land on somebody (9-1-11-b-1).
2) Other players may only leap from within or behind the NZ and land on somebody (9-1-11-b-2).
In your original scenario, if the leap starts from within the NZ, it is always legal, no matter where the player was at the snap.