stopping joint animation/attaching things to joints

I have an animated character and can control any joint with lateUpdate(). That means I'm always updating that joint to the same spot, however. I just want to place a few joints of a character initially, based on some user selections (e.g. hat placement), then tell those joints to stop animating. They would still need to move with their parents, of course, just not move of their own accord.

Also, is there a standard method to attach an object to another, e.g. a separate hat object to an animated head joint, so it follows along with the head?

Thanks!

Edit: I found the answer to the 2nd question here:
http://answers.unity3d.com/questions/7448/attaching-an-object-to-a-bone
I had searched before, but somehow missed it.