Once a flight is unrealistically scheduled, all bets are off if the flight actually returns after midnight. I was scheduled on a passenger leg that departed MCO to CVG at 2000 with a scheduled arrival of 2230, then was to ferry home to CMH arriving at 2350. A late passenger does not trigger the two extended day option unless this delay causes you to arrive after 0300. If that was the case, you would then be entitled to the two extended day option. You would still be entitled to one extended day or one comp day of your choice.
Late passengers produce multiple issues under the contract.
Also, the company must schedule a buffer of 30 minutes to the scheduled block in time of the passenger leg. That means that if the company schedules you to a passenger flight, on your last day, that is scheduled to arrive at a time between 2331 and 2400 local domicile time, and the passenger shows up late enough to require you to fly them past 2400, you are not obligated to accept the trip under 19.4a. Remember though that a late passenger does not relieve the company from the exact 14 hour duty limit found in 28.2c. I recently was given a return flight home that was scheduled to arrive at 2345 but would have required me to be on duty for 18 consecutive hours. I refused this flight and went to a hotel.