It sounds as if this car has seen more than its share of major repairs. In and of itself, that's not a bad thing, but unless you can get it FILTHY cheap, with the prices of the124 cars as low as they are these days, I would think that you would be money and time ahead with a more solid example.

Getting to details:

Rust on the rotors is no big deal. They will be shiny the first time you drive it around the block.

The fuel system issues. This one is a roll of the dice. If you can find someone that is very experienced with the Bosch KE Jetronic, then you could probably sort through it. It sounds as if the mechanic was a parts changer that didn't understand this out of the ordinary system.

I hope this helps.