The official pace requirement is 16min/mi based on the "balloon ladies" who are the official last starters of each race. That means 1:33:30 is the maximum amount of time they will be on the course. Assuming they cross the start line at 6am, that means you need to be able to finish the race before 7:33am. The rundisney website says to train for at least a 15min/mi pace, and this is a good practice to follow because you will likely cover a longer distance than the officially measured course tangents.
Now, if you start 5 min ahead of the balloon ladies (say the front of corral D instead of in the back with said ladies) you would be able to be closer to a 17min/mi pace. If you stop and wait in line for 5 min that is still "on the clock" and you would need to be a lot faster than 16min/mi to "make up" for that waiting in line. Just because YOU stopped doesn't mean the clock did.
Could you stop for characters? Maybe. The lines at the beginning of the race are usually a lot longer than the lines at the end, but if you already know that you tend to be *slower* than the sweep pace, you may find yourself hurrying along to avoid the sweepers and decide to forego the potentially shorter lines at the end. I would encourage you to get to your start corral early, and try to be as far to the front as you can, to give yourself as much of a time buffer between yourself and the "sweep line" (balloon ladies) to maximize your opportunity to be able to stop for a pic or 2 along the way.
