My friends DD just started shaving her legs at 9. The friend didn't know & if she had she wouldn't have let her just yet, but she's decided at her DD's age, she needs to pick her battles & this is one she'll leave alone.
Her DD did have quite dark hairy legs & she was getting self conciouse about them, as well as having other girls mention it.

I, personally won't be letting DD1 til she's older. High school probably. She'll be 11 then. Same age I was. She is blonde though. DD2 might be different, as she's darker.
The hair thing I think I'd wait. Mum permed my hair at 12, it was dyed the first time when I was 16. I let them put hair spray etc in, & might let them rinse in high school, but I don't think I'd let them dye til they are about 16 either.

But mine aren't there yet, so you never know.