Congratulations. I think you have a real bargain there. No chance IMO of running those vac pumps on single phase as the motors will draw far too much current. A vac bed will be fantastic for work holding, but I think you would be better to try to get a 3ph. supply or else sell the two pumps (you could get up to £500 each on a good day) and buy a couple of smaller single phase units.
Keep abrasives away from the rails. WD40 and pan scouring pads are probably the best remedy for surface rust. Good luck. G.