They should be fine in the microwave. I haven't made them myself, but my mom used to make twice baked potatoes for us all the time, and she would always make extras for us to have the next day.. They were always good out of the microwave, the biggest problem I ever had was the middle was still cold when I took them out! I think as long as you make sure the middle is hot they will be good!
When life gives you lemons, make grape juice. Then sit back and watch the whole world wonder how you did it.