Hair extentions at the BBB? And cool dude?

[Livin'4Disney]

Hi,
What exactly are these hair extensions I keep reading about? How long are they? My daught has chin length bob cut with a little wedge in the back. Is this going to work for her? She want to get the diva style?

Also, I have appts. for DS3 and DS9 to get the cool dude. How long to these last with pixie dust, mickey, etc?

Thanks for any tips