What about 4 large pockets to hold 6 folders in each.

I am a retired 1st grade teacher and I had metal lockers in my classroom and used folders on the lockers which I sanded down after several years and painted each locker a color in the rainbow, also made curtains to match. I think it would really depend on DD's classroom and where she might be able to hang the quilt- we had limited wall space, due to bulletin boards, windows cabinets and chalk boards. Instead of making it a regular quilt size, perhaps make it a long rectangular quilt with no more than three rows high, so the little ones could reach the pockets. I like the idea of the chair pockets using the fishbowl theme and perhaps the quilt done in a small normal quilt shape with the pockets pulling in the theme of the quilt. This way she could change her theme later and still have the fishbowl quilt to use sometime in the future. Perhaps make two or more vertical wall hangings with pockets and hang next to the quilt, having students draw their own fish or sea item, laminate the picture and enclose the picture in a vinyl pocket or close pin it to the vinyl pocket. That would be a great first day or couple of days school project and the students would feel they really owned their own pocket if they made it themselves. Kids love to help decorate a classroom with their own art work or school work, or at least my students always did.

Be sure to get some fire retardant to spray on it, or they may not let her hang it in here classroom. I have made several for my teacher/daughter and they have to be fire retardant or she cannot have them in her classroom. My daughter ordered a fire retardant from Amazon. Just a thought.

So nice you want to help your daughter. The thought and the idea are great, but not practical in practice. This is going to sound like I'm being negative (I am, but in a good way), but you are going to run into a LOT of issues with this project.
POSITIVES: Very cute, bright colors, each child will have a fish bowl, each child will know the name of a different fish
You can make it out of denim (denim being strong and can hold up to some weight), with the bowls on the front of each pocket
NEGATIVES: You will need to have about 25 pockets, due to class sizes changing all the time
How high it will be hung, 1st graders come in ALL different heights (if someone is a little short and the pocket is a little high jumping and pulling are bound to happen), pockets will get torn
Maybe you and your daughter might think about a pocket for the back of each students chair with a fish bowl on the outside. The pocket can be tied to each chair, then the student can place the folder into the pocket when they come in and sit down. Your daughter can walk around and collect the folders as she wants them (by rows or all at once). This would be a lot of work for you, but a lot less heartache when the quilt gets damaged. Just a thought, good luck and be sure to post pictures of your finished work.

I would use those plastic vinyl for pockets so it could be cleaned easily rather than fabrics, seems it could tear, ravel from so many inserts,withdrawing of projects. Would seem like to make it 2-3 rows long so all students could reach their designated pockets? Just saying.......

I think I'd make a durable folder collector with a longish top to it. Then attach the wall hanging to it. That way, the WH won't get damaged with the in and out of the files.

Since I don't know the configuration of her classroom this may not work, but how about making it long and narrow so it hangs below the chalkboard. That way it would be easily accessible. Might even more or less wrap most of the way around the room. And I would go with using fairly heavy denim for the back and pockets, decorating each one with individualized fish bowls and a clear vinyl slip in window above or below the fish bowl for the child's name.