Defining Freak Magic: Magic that is done for shock value, and usually incorporates elements of horror, or self mutilation. Rooted in American Sideshow.
Defining Kids Show: Shows done for children, usually between the ages of two and ten. Common elements usually involve very visual magic, balloons, juggling, or comedy.
Usually these two never meet. Parents that book kid show magicians want someone to entertain their kids, not give them nightmares. Also when you're doing a kids show, unless you're doing something all freak related, doing something like thread or saw will seem disjointed and out of place. Yes it is indeed very visual, but if the rest of your set consists of cups and balls, sponges, and cards pulling thread out of your eye may just be a bit too out in left field. Theatrically speaking, it doesn't belong because it doesn't fit the overall story. -Theming is a rant for another thread.
So I would say putting elements of freak or geek magic into your kids program is a risky move. It may work for you, it may work against you. It's a gamble, and not one I'd take.
Doing all freak magic for a kids party is probably not going to go over well either. Chances are good you'll never get booked to do freak unless the kids birthday is at the end of October, and they want a spooky theme. Doesn't mean it won't happen, I've occasionally gotten the phone call to do a kids party, (just did a one year olds Alice in Wonderland as the Mad Hatter three days ago) and after my usual response of "Are you mad?" is out of my system I go about making sure the client knows what they are getting me into. Once the client knows what they are asking me to do, and what I am able to do for them, everything is a go.
I guess the short answer to a long reply is No. You typically wouldn't want to do something freakish for a kids party, and you probably won't book out freak magic specially for kids parties either.