Brake lines W123

[MS Fowler]

On the 240D I am considering buying, the MD state inspector says the brake lines to the rear look rusty, and MUST be replaced. I've done steel brake lines before, and can handle the double flares if needed. I plan to buy steel lines with fittings and then bend to match the originals. My questions---
1) My experience on making brake lines is on US cars, I am assuming that metric threaded lines are readily availible. Is that correct?
2) Are there any special problems that I should know about?
3) Do the lines usually come out of the hoses and other threaded fittings easily--or do they typically corrode?
4) The parking brake also failed---Is there a typical way they fail that I should look for?
Sorry my questions are a biy abmiguous, but I have not seen the car yet--all my information so far is verbal.
Thanks to all for your help.