Late entering player

[Kalle]

I've sent this play to RR and here is his answer:

RR: Assuming that A35 does not become the 5th player in the backfield, the play is legal.

I for one stand corrected. Thanks pedja.

[NTXRef]

Boy I have a real problem with that response.  As outlined by Ump, all offensive players must come to an absolute stop... (7-1-4-a).   Somebody running on from the sideline is an offensive player, so why would this rule not apply to him.   I've still got illegal shift.

[Kalle]

The offense must be stationary if there is a huddle or a shift. I think the reasoning behind this ruling is that if one player is moving it cannot be a shift (it obviously does not create a huddle). It is simply one player being in motion, even if the said player became a player after the rest of the players stopped after a huddle/shift.

[Diablo]

The offense must be stationary if there is a huddle or a shift. I think the reasoning behind this ruling is that if one player is moving it cannot be a shift (it obviously does not create a huddle). It is simply one player being in motion, even if the said player became a player after the rest of the players stopped after a huddle/shift.

Consider a related play
Team A has a huddle with 11 players.  When the huddle breaks, A80 jogs directly toward his sideline and exits the field of play into his team area.  Either (a) while A80 is jogging off the field or (b) shortly after A80 steps out of bounds, A86 jogs onto the field of play.  After A86 is inside the 9-yard marks, but while he his still running to his position, the ball is snapped. His movement is otherwise legal (not forward, no other players moving while he is running onto the field.)
Rulings?
For simplicity, ignore any 3-5-2-e considerations.

[Kalle]

Consider a related play
Team A has a huddle with 11 players.  When the huddle breaks, A80 jogs directly toward his sideline and exits the field of play into his team area.  Either (a) while A80 is jogging off the field or (b) shortly after A80 steps out of bounds, A86 jogs onto the field of play.  After A86 is inside the 9-yard marks, but while he his still running to his position, the ball is snapped. His movement is otherwise legal (not forward, no other players moving while he is running onto the field.)
Rulings?
For simplicity, ignore any 3-5-2-e considerations.

I was going to say "simple, 3-5-2-e applies" but...

Ignoring 3-5-2-e and with the ruling from RR, I would have an illegal shift in a) and a legal play in b). And no, I'm not very happy with this, but I can't see how the action in a) could be legal - where do you draw the line, 9-yard marks?