Trying to figure out if i should replace these, they look like rubber body mounts





And is this an anti vibration piece connected to the mount for the rear differential?

 

The first picture looks like a subframe mount and it does look like it needs to be replaced. Do you have any clunking while steering or accelerating? The second picture just seems to be the mount for the differential, you are correct in it being an anti vibration piece because the rubber in the mount provides reduced noise and vibration for the diff.

 

Holy rust, batman!

 

While you're at it, replace all those rusted parts and undercoat the car to prevent further rust.