Personally I freeze the finished product and have never had any issues with them once the are thawed. I have never frozen the batter I know this can be done but don't know to what extent it changes the batters properties, plus at least you can rest in the fact knowing you have finished all 60 cupcakes to completion then just decorate on the day or the day before. Happy baking!
Bake them all ahead of time. Let them cool then place in large ziplock bags and try to remove as much air as possible.
Feel free to take them out of the freezer just before you want to frost them. You can frost them the day before the birthday then let sit out. You do not have to refreeze them after you frost them, they will stay fresh up to one week.
I hope this helps. Good Luck and Happy Birthday to your Son!
