I can help you with the first two issues.
Section 839 of the Penal Code allows someone seeking to make an arrest to summon someone else to assist in the completion of that arrest. Case law states that the person who is summoned may make the arrest just as if it was committed in their presence, even though it was not. More than likely the officer who spotted the violation was, for some reason or another, unable to stop and cite you personally, so he asked a second officer to do so on his behalf. When that happens, the “not in my presence” box gets checked. Should you go to court on this citation, the officer who actually witnessed the violation will appear to testify.
With respect to the length of your stop, I would offer the following.
First, you have to stop at a limit line, if marked. If there is no limit line then you must stop before entering the crosswalk on the near side of the intersection. If there is no limit line or crosswalk, you must stop at the entrance to the intersecting roadway. If you don’t stop in the specified places, it doesn’t matter if you sat there for 30 seconds, a violation has occurred.
Next, most people hit the brakes, feel the car strongly lurch forward and will swear on a stack of bibles that they have come to a full and complete stop because that is what they honestly believe. However, until you also feel the car rock backwards you have not come to a full and complete stop, you have only slowed down. This is where most people get cited for stop sign violations. It’s a bad habit many drivers get into. Hang out at a stop sign for 15 minutes and count the number of violations you see. You’d be surprised.

