Ok, so we know we need the Lvl 25 baby pokemon for little league for easter event right? Why not just make it so everytime you decide to do it, they would turn into lvl 25 instead of having it at lvl 25 since we all accidentally Lvl up our little league mons to 26 and can't use it anymore.
For example, I have a lvl 100 munchlax, I battle little league and instead of it being lvl 100, its lvl 25.