I would have left Dansby down last year - and held out til the home opener in 2017.
That probably would have cost a win, and gotten us an extra year of control
I really think you're overestimating the effect resting the starters would have on attendance. By August in 2015 and 2016 attendance was already sitting well below 50% of capacity for most home games, even dipping down into the 30-35% area for weekday games. At that point you can see attendance went up when teams like the Mets, Nats or Yankees were in town, which had less to do with what the Braves were putting on the field and more to do with who they were playing.