OK Let me try:

IMHO This is not a question of the definition of a catch. If it were we wouldn't be talking about it. This is a case of IVE or officiating from the booth. AB has quoted the philosophy given Replay Officials straight out of the NCAA Rule Book. It is very demanding when the RO reverses a ruling on the field
1. Does the airborne receiver gain possession and get a body part down inbounds? (:37) Is left elbow down OOB - No IVE. Was the airborne receiver NOT in possession of the ball? Questionable but no IVE. A case (based on rules application) can be made that possession is accomplished. Forearms can be used to grant possession. No IVE? On Field official rules possession and body part down.
2. Does airborne receiver maintain possession of the ball through contact with the ball? 1:21 indicates the ball does touch the ground. Does it clearly show (IVE) that the receiver has lost possession of the ball as a result of the initial contact with the ground. Maybe but only maybe. It could indicate loss of possession or it could indicate normal movement of the ball but not loss of possession. On Field Official rules possession not lost.
3. Does the receiver lose possession as he slides OOB? 2:18 and 2:33 gives strong indication the receiver has the ball firmly grasped to his torso with his forearms as he slides along the ground. On Field official rules he does not lose possession as he slides along the ground.
Do we have IVE (based on NCAA guidance) to overturn the On Field official??