Attacker doesn't necessarily get first shot. In fact because the attacker is maneuvering rather than holding steady, it's harder for them to get the first shot because when a tank in CoH moves, its turret turns to shoot whatever it wants instead of what you want it to shoot. The defender, meanwhile, could just target the attacker because the defender doesn't have to move. Whoever gets the first shot pretty much depends on whose gun has the longer range, though.
This is true. There's tons of different possible scenarios. Attacker is moving while positioning, too so it gets penalties. Defender turret could be aiming elsewhere and not respond by the time the enemy landed two. Defender could have vision and range to attacker, while attacker only has vision but no range, etc. The only way to prove how true this is, is in an actual battle with the system in. :/
A crappy image to illustrate the point:
Wouldn't this interfere with the way tanks aim at infantry?