Deep down Pedro wants to. He loves Johan already. I mean, the other day, Pedro gave Johan his blessing to be the Opening Day Starter. Like that wasn't going to happen already...
It might not have. It's purely ceremonial, and a lot of times teams will give it to a veteran who has been on the team the longest. After the first time through the rotation, the order doesn't matter again until the playoffs.
Not sure if this was part of the thinking, but by pitching game 2, Pedro will start the home opener which is also pretty ceremonial also. I agree in general about rotation slots being pretty meaningless. Considering off days, injuries, double headers, etc. how often does a #1 truly face the other team's #1, 2 vs 2, etc.?