3) Defense does not get false starts. If they are on the line of scrimmage when the ball is snaped its a neutral zone infraction. Crossing that line by any defender would be an offsides infraction. All of this doesnt matter until the ball is snapped.
A false start happens when an offensive guy moves his feet prior to the snap. (Or tries to simulate the snap) QB's are notorious for trying to draw defenders offsides.
Really there are offensive strageties that move alot of players presnap to draw defenders offsides or confuse defensive assignments. But, they the players that can move presnap are guided by a set of rules that allow for the formations you generally see in every game.
I think only one player in side the Tackles is allowed to shift at one time. While the players lined up outside the Tackles can shift at the same time and noone on offense is allowed to be moving at the time of the snap.
Another is you have to have two eligable recievers that line up on the line of scrimmage on every play. Every other eligable reciever cannot line up on the line of scrimmage. Only seven of the eleven are allowed to due that.
Any penalty that cannot be enforced completly will be half the distance, but the penalty rules are even different if that infraction happens in the endzone.
If a DB get a pass interference call in his dzone. It is not half the distance. The ball is placed at the goaline.
A hold by an offensive player in his own endzone is a safety.
And alot of other crazy rules. If you kick the ball on the ground like a soccer ball to advance a fumble that a penalty.