Can I make 12 larger cupcakes from a mix that says to make 24 cupcakes or will it mess up the balance of the cupcake (like overflow while ba

Yes I've made 12 lg cupcakes from my dz batch before... I will say though that they will take longer to bake. So in the past, I have turned the oven down just a bit from original temp (if it says 350 do 325) that way the outsides aren't to crispy.

Sure! Just be careful to not overfill the pan.