Thank you! ^^

Unfortunately, I didn't make those two wigs, they were bought from another maker. However, I intend to start doing my own wigs for them, since I do know how. ^^ Here is a link to a tutorial about how to make mohair wigs the way I do; Making a Mohair Wig for your Fashion Doll . There are also other ways, of course, so here is a different one; Tiny Mohair Wig Tutorial - Antique Lilac .
But these are just if you're going to create a wig. You could always give them permanent hair by pulling out all of the hair the factory put there and root in new strands of hair. Here you have a tutorial on how to fully customize a Monster High doll, including rerooting her hair; Nuu's Cusps: Doll Customising: Monster High Dolls - Prepping and Rerooting .

I actually never altered any of my Barbies as a kid, but I do remember wanting to. I guess I didn't want to ruin them haha! Instead, I ended up getting into Ball Jointed Dolls and painted them all myself - I'm quite picky about that, so I figured it'd be best to learn how to paint them myself. Besides, it has saved me a LOT of money in the process!