First one to get direct answers to these questions from an Authority Having Jurisdiction wins!
For these scenarios, assume a team B player that gets contacted at or below the thigh is NOT in contact, and has NOT just disengaged from contact with an opponent.
1) At the snap, interior lineman A66, with no opponent directly in front of him, starts to move forward when his foot slips and he falls to the ground, having contacted no one. As his teammates are completing their blocks, A66 is able push himself up off the ground into a crouching position, and successfully begins to move forward. In a continuous motion in a crouching position, A66 blocks B99 at the knees, from the side, and at a point not more than one yard beyond the NZ. All action occurs within the tackle box, and while the ball is still within the tackle box.
Ruling:
Issue: Is this A66's "initial charge," since, immediately after the snap, he fell to the ground before making a charge that led, or could have led, to a block against an opponent?
2) At the snap, interior lineman A66, rises from his 3-point stance (or from a hands/elbows-on-knees stance) and then dives at B99, contacting B99 at the knees from the side, at a point not more than one yard beyond the NZ. All action occurs within the tackle box, and while the ball is still within the tackle box.
Ruling:
Issue: Does A66's actions constitute an "initial charge?" Or, is an "initial charge" a movement by a player who immediately moves forward while simultaneously diving, with the apparent intent of contacting an opponent at/below the thighs?
3) At the snap, interior lineman A66, with no opponent directly in front of him, moves forward from a three-point stance, in a crouching manner, and with his second step, clearly changes his direction and contacts B99 at the knee, from the side. All action occurs within the tackle box, and while the ball is still within the tackle box.
Ruling:
Issue: Does an "initial charge" have to be in a direct line? Or, does a distinct change of direction terminate the "initial charge?"
There are probably more, but those will get us started.