I've never had a fox bike.
Post some pictures it will help big time on figuring out your issues.
Worn out sprockets & chain
Poor alignment. Could come in to play.
Have fun with your project!
I now have a working hydraulic front brake & cut out my mud guard out of black acrylic sheet. I'm now In the process of moving backwards, just when I thought I was done with the rear end. I've decided to add a chain tensioner to swing arm to make up for the run out in the rear wheel.