The first one is not Pass Interference (my opinion). There is incidental contact between DH and the DB until the ball arrives. They both had their hands on each other. As the ball arrives, DH tries to come back to the ball and the DB face guards him. He then tackles Deon after the ball arrived. It is not against the rules to face guard in college. The DB doesn't have to look back to shield the receiver from the ball. However, that incidental contact is more times than not called. It's easier to see that in the Vine because it's slowed down.
The second is only interference if the receiver's motion is impeded. It didn't look like it was, but when the hand is on the shoulder, you ain't getting that call, regardless of why it was there.