Question re illegal forward pass

[Fan10]

I'm a fan here, and I tried to find the answer in the rule book at ncaa.org, but I must not be looking in the right place:

If on 4th down, the QB crosses the line of scrimmage and throws an illegal forward pass beyond the line of scrimmage and the pass is caught for a first down, I know that the defense will have to accept the penalty because declining it would result in a first down. So, when they accept it, is the 5 yards marked off from the spot of the pass and then the possession goes over to the other team five yards from the spot of the pass?

(B) If this is the case, what if after the five yards is marked off, the ball is still past the line to gain?

(C) If the QB passes beyond the line of scrimmage on a 2 point conversion and it's caught for an apparnet successful two point conversion, is the try simply no good and we kickoff?

Thanks in advance.