What would you have if the foul was a facemask with the same scenario? B clearly grabs the facemask in the field of play at the 1 yard line just before the A ball carrier crosses goal line, and while the ball carrier is in the EZ we have the twist and pull component of the foul?
Tougher sell since the point of the pull/twist is less obvious than the point of the tackle, but my thought process would likely be the same. The only caveat in this scenario is the idea that "we're not THAT good!" -- basically, we should officiate the obvious actions and not try to split hairs where we can avoid it.
Both HCT and facemask are typically live ball fouls, so the default enforcement would be as a live ball foul. However, the timing of the foul relative to the score complicates matters greatly. Since the score ends the play, what would normally be simple live ball actions are clearly done in a dead ball situation.
There may not be a definitive answer in writing, but without information to the contrary I'm comfortable with dead ball enforcement.
