I don't know about the pixie dust but can testify to Harmony being a terrific place for a haircut for any age.
I got one of the most flattering ones I've ever had there to repair a purely awful one from a (Not So) Great Clips at home right before we left.
And for far less than the WDW salons charged.
Are you sure you want pixie dust all over everything? I got some once several years ago and found that it scatters EVERYwhere. I was still seeing it in pockets and seams months after we got home even though the clothes I wore that day had been washed several times.