Do individual states have the authority to change some of the mechanics that are published by Fed?

Sure. And some states (and many, many umpires) don't use them at all.

Individual associations often, and rightly, discard FED mechanics.

My association uses pro mechanics and keeps updated with the changes PBUC suggests each year.

FED treats mechanics as a static element of umpiring. FED does not study or experiment. Both CCA (college) and Pro experiment, survey their umpires and study what works and what doesn't work as well.

Thank you.
Here in Illinois, on our state website, there is a mechanics powerpoint presentation. But, there were changes to the 2009 baseball mechanics that are not up-dated on the site. Which is why I will asking some mechanics questions. Hopefully my fellow state umpires will be able to help me out.