I just went through some of these same things.

1. I actually received the same advice that schudel5 provided, but then I thought, can I just pull up the ball rails with my hand? Turns out I could. I gently pulled straight up from the post ends (like I were using a hammer) so that I didn't bend the rails, with a little gentle force they came right out.

2. In my earthshaker I did find locktite. I had to heat from the bottom with a soldering iron, careful not to burn anything else and while heating unscrew the post. Then yea, I am replacing with new hardware.

As for the third question, I'll leave that to your own skills. It mostly depends on how much you are going to do yourself to the machine.

Good luck.