Depends how long they've been in the ground, if its more than a couple of years, getting them out and potting them up will likely kill them, roses put down long roots. Unless they're the small patio type roses, you haven't said what kind they are.

What won't kill them is being trampled on or broken a bit, so as long as the workers don't actually put piles of stuff all over them for weeks on end, you should be able to cut them down, feed and let them regrow. The ones to worry about are any standards - you don't want the main stem broken on those.

Yes, good point. Roses are tough. Why not put some loud coloured safety tape around them to make the workmen aware, and hope for the best! Good luck! The loose rough cast that falls to the ground makes great drainage in pots I find! :)