Team A is lined up with 8 players on the line of scrimmage. The wide out and the wide slot man stay standing. After everyone is set, the slot man shifts back 2 yards and sets as a back. Did he false start since he was not on the end of the line when he moved?

No false start. The action does not meet the requirements of 7-1-7a-c.

As you stated, when the slot man moved (a) his shift did not simulate a snap, (b) the movement did not cause B to encroach, and (c) the only prohibition to any player on line between the ends from shifting is if he placed his hands on or near the ground. If he does so then any movement of the hand whether quick or otherwise constitutes a false start.

Therefore since the slot man stayed standing and did not place his hands on or near the ground he was free to shift provided his movement was not so abrupt as violate 7-1-7a-c.