I am not sure how long these classes are , but when I was in the scouts our art classes had 1 day of leather,1 day of wood, 1 day of braiding,and every day was an archery class.
Sounds like you have a good handle on it. Remember that whatever you know about leather is most likely 100x's more than the kids. So as long as it is fun they will have a blast.
I think something that everyone has missed is a <Small Pouch that can be tied around the kids waist with some rope. They can add their names and maybe some border stamps. And of course paint them...that is something they would really like I think.
Bracelets are cool, the only thing about the string is after it is on it will be almost impossible to get off, and if it is snapped, they will most likely loose them, so ...ya tying them is better:)
Since you have an archery class, why not make some arm guards..if you have enough leather for that.
That is just stuff off the top of my head, and it sounds like you are on a good path!
I just thought I would add my 2 cents:)
Have a great Summer!