My car is squeel-less so I'll chime in.
1. Removed both brake sensors (RR and FL) and zip tied. I change them frequently with my track pads (PFC08) so always checking pad wear.
2. Added antisqueel to all brakes. I also put some on the prongs in case that caused a small squeel.
3. I pushed back on all the dust covers to give more clearance. If you look at the OP's pics you can see the piece that has rust is connected to the dust cover. If you push on the dust cover enough you're also giving room for where it might touch the rotor. This actually ultimately solved my RR squeel.
Car has been squeel-less for about 15k miles now.