Here is my take on the ESPN option.
The ACC signed a 12-year TV deal with ESPN in 2010. In 2013 the ACC members, reacting from the departure of Maryland agreed to the GOR they all signed. In 2016, ESSPN agree to launch the ACC Network beginning in 2019. At the same time, ESPN agree to extend the TV deal to 2036 conditioned on the ACC extending the GOR to 2036. It has been my understanding, based on my neighbor's contact with the UNC AA, that the TV deal is not part of the option, which is only about the ACC Network.
Think about the SEC deal as compared to the ACC deal. If ESPN dumps what is now relatively cheap broadcast rights and fills those slots with relatively expensive SEC games, they will be losing revenue compared to the ACC. Or, they could fill those slots with G5 games. It just doesn't make sense. Also, while the ACCN might not be the brightest star in the sky, it's an easy parking place for ACC games that will not have huge ratings.
I have no 1st hand info, but I think the deal with ESPN is good for them and the ACC. We'll see.