I know how to do the princess up-do, but not sure I can explain it. I'll try.. but you need to practice before Halloween so we can get it right.
First brush hair and make a very high ponytail. They used lots of gel to make it perfect. Then take a small strand of hair and wrap it around the pony holder to cover it. Secure with a bobby pin.
Now you need a bunch of the really cheap, thin pony holders. Secure them to the ponytail about 2" from the top, and then about every inch after that. So now you have a ponytail with elastics secured all the way down. Here is the tricky part. Take the hair and roll it up, 'till you reach the 2nd to top elastic. The hair that is between the top 2 elastics you need to pull and fan out. Tuck the rest of the ponytail (that you rolled up) under and pin it all in place. Push tiara in front.
I can do it to my DD and take pix if you all can't make sense of this. Just PM me.
-Sherry