Nope, I was just making sure that she has another adult to stay with the 2 year old during the rider swap.
The way rider swap works is the whole party will go up to the CM at the queue with their park tickets. They will let the CM know they would like to use rider swap and who will be riding first (Group 1), and who will be staying back with the too short child and riding second (Group 2). The CM may or may not measure the height of the too short child (to make sure they are too short), but they will at least need to physically see them. The CM will then add the rider swap pass to the tickets of those who will be riding second. Up to 3 people can have the rider swap pass added to their tickets, and that group of 3 can include people who are riding in the first group. Then, those who are riding first (Group 1) go in the appropriate queue (FP if they have FP or standby if they do not) and ride. Meanwhile, those are who are staying back with the little one (Group 2) can get a snack, use the restroom, ride another ride that's close by, whatever. After the first group is done riding, Group 2 will go into the FP queue, scanning their ticket. The rider swap enables them to enter the FP queue regardless of whether or not they have an actual FP for that ride. They ride, then meet up with the rest of the party.
The rider swap return time is calculated by the wait time of the queue that the first group goes in minus 10 mins, and ends one hour after it begins. For instance, if Group 1 goes in the FP line at 4:00 and the posted wait time is 15 mins, then the rider swap window begins at 4:05 and ends at 5:05. If Group 1 enters the standby line at 4:00 with a posted wait time of 50 mins, then the rider swap is valid from 4:40-5:40. Since the rider swap has a small window in which it can be used, it is a good idea for Group 2 to stay semi-close to the ride while Group 1 is riding. Each person can only have one rider swap pass on their ticket at a time.
When scheduling FP, your friend can schedule the height-restricted rides for those who will be part of Group 1. Group 2 can use their FP for a ride with the too short child that is nearby at the same time, or schedule them for something later. For instance, if Group 1 is getting FP for SDMT, Group 2 might want to get them for Pooh, since it is nearby. They would still all go to the queue for SDMT to have the rider swap added, then Group 2 could go and ride Pooh while Group 1 rides SDMT, then meet up and swap.
Hopefully this makes sense.