M.L.
My sister and I do all of that! My sister is in Fort Worth, not sure how far from Allen that is. She is a professional clown, but will come in non-clown attire if you request it. She is excellent at all of the things you want and great with kids of all ages.
However, for balloons/facepainting and magic show, that is going to be more about 2 hours for that many kids.
Here is her website:
http://partywithpookie.com