I believe that was the new starter, after they re-released the set with a consistent (and larger) vehicle scale. There has since been several releases for the various theaters, and WotC relased new revised unit stats on PDF as well.
Can units shoot at an enemy unit behind another one?
Does an attack on one unit in a hex affect other units in the same hex?
On a sucessful cover roll, can the attacker resume his attack with the effected unit?
Units don’t block line of sight. When attacking you have to declare a (valid) target unit. Only units with blast will attack every non-aircraft in the hex.
“On a sucessful cover roll, can the attacker resume his attack with the effected unit?”
I’m not sure what you mean.
Attacks go as follows:
Attack declares target and rolls appropriate dice, counting successes for hits, etc.
If the defender is in cover and takes hits he does a cover roll; on a 4+ THAT attack is limited to disruption.
Procced to the next unit.