Here's a good example of a rusted pivot ball starting at 15:58 in this video. It's part of my ATX to MTX swap so ignore the rest of the video if you want. I show how to install the axles, tie rods, pivot ball, hubs, caliper, rotor, you name it.
Mazda 626 - ATX to MTX Transmission Swap Part 8 - YouTube
In your case the metal on metal could be coming from a loose tie rod or lower control arm pivot ball plus a squeaky shock. They all work together with each other so have multiple components making a noise at the same time could be possible.
Oh and in case anyone is interested... the axles and transmission are from a 1994 MX-6 going into my 1995 626.