There was a slight typo in the original question, and I mistakenly added another in fixing it. It should have been:

12:10 AM - Transaction 1 on QotDDatabase begins

12:11 AM - Transaction 2 on QotDDatabase begins

12:12 AM - Transaction 2 on QotDDatabase commits

12:13 AM - Transaction 1 on QotDDatabase commits

12:14 AM - Full backup data reading of QotDDatabase begins

12:15 AM - Transaction 3 on QotDDatabase begins

12:16 AM - Transaction 3 on QotDDatabase commits

12:18 AM - Full backup data reading of QotDDatabase ends

12:19 AM - Transaction 4 on QotDDatabase begins

12:20 AM - Full backup of QotDDatabase ends

12:21 AM - Transaction 4 on QotDDatabase commits

In this case, 1, 2, and 3 are included, 4 is not as it starts after the data reading portion of the backup ends. I'll award back points to people since it was confusing.