Other mistake: Since Annie had completed the terrarium the group should have at least received a passing grade since the Professor made them a group of 7.
Introduction to Finality - S3-E22
Other mistake: During Leonard's "Let's Potato Chips" YouTube video during the ending credits, you can see the video reaches the end of the load/play bar (watch the circle), yet the video continues for several seconds. Once the circle reaches the end of the load/play bar, the video is over and won't continue.
Lawnmower Maintenance & Postnatal Care - S6-E2
Other mistake: Britta hits Abed in the face with a pillow, swinging in from the right, but when it connects, his face swings the other way, the same direction from which the pillow came. (00:16:50)
Answer: The implication is that Jeff will still be teaching at Greendale after Annie and Abed leave. As for who became vice dean? It's never shown, since it's not really important to the series.
TedStixon