the drive through for passing under yellow flag would be a good thing, but would be hard to implament atm, cause when someone leaves the pits, they are put in front of you, so your position changes and then back once you cross the line.
the crossing the line, it can have the same principles as the start finish line, where as when you cross that, your laps increase, lap time resets etc, but instead, it can form on the pit lines, and have it so if you touch it(after leaving pits) then you auto get a drive through, or maybe a time penalty.
the cutting, i think that would be very hard to do, and the hitting from behind, again, too many variables.