The rear rust looks like it's on the outside circumference - to be expected if the pads don't contact there. Like Tom W said, if the pads are too small, worry, otherwise I would only concern myself with the front warping issue.

Have you replaced the front bearings at any time? If so, make sure the inner races are seated square, bearing play is correct, and that the rotor sits evenly flat against the hub (i.e. no rust buildup on the hub face). Then new rotors & a good bleed up front.

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