Am I right in thinking from a comment on a different thread that you are trying to play without your own rulebook? If so, I can only recommend that you invest in the EASLRB which can answer many of the questions that you are posing. This forum is really intended to clarify rules as opposed to saying what they actually are. I would also recommend that you download VASL so that you can produce diagrams if you are seeking help with a particular situation. Having said this, I have attempted to recreate the situation that you describe.
View attachment 22751
My first comment is that, in my view (with which others might disagree), the squad with the ATR does not qualify for street fighting advantage. For further clarification, I would recommend that you read this thread:
11.8 STREET FIGHTING: Any vehicle in a road hex and ADJACENT to a building hex on both sides of that road is especially vulnerable to CC in that hex.17 All Infantry advancing into that road Location from ground level of one or more of those adjacent building hexes qualify for a Street Fighting...
www.gamesquad.com
Leaving this aside, let's assume that street fighting does apply. When the S35 expends a MP to start, it becomes "non-stopped". Therefore, the +2 DRM for a "motion/non-stopped" vehicle will apply to any CC reaction fire attack. If, instead of or in addition to, attempting a CC reaction fire attack, the 467 decided to fire its ATR, the S35 would not qualify for Case J since (per C.8) it is not yet a moving target due to its not having entered a new hex in its turn. Case L (point blank fire) would however be negated since it is now non-stopped.
If the S35 chooses to reverse over the wall, it will cost it 9 MP to do so (1 to start plus 2 to cross the wall and enter open ground multiplied by 4 for reversing).
When using street fighting, CC reaction fire is only possible if the unit making the attack and/or its SW is not marked with a first fire counter. Therefore it can only CC reaction fire once unless the AFV then enters its hex.
Provided that the 467 has not used subsequent first fire, the ATR can be fired upon further MP expenditure by the S35 or later at a different target.