Agree with pretty much all of DB's comments.  Definitely replace the calipers with SS sleeved ones, the originals are very likely corroded beyond rebuildable.

Though I would recommend going the O-ring route.  When I first rebuilt mine, I went with the lip seals.  I would consider mine to be driven regularly (6000+ miles/yr), but I still had one seal fail within a few years.  After that, I converted to O-rings, and no leaks since.

But if you do stick with the lip seals, I would be cautious with the vacuum bleed method.  I have no experience with this myself, but some on CF claim it's possible to suck air past the lip seals and into the caliper, therefore never achieving an air-free system.  Sounds feasible in theory I suppose.

I built my own pressure type bleeding system with a spare master cylinder lid, a couple of air hose fittings, some 1/4" foam seal, and a little silicone to seal up the holes.  It will hold around 12-15 psi without leaking past the seal.  I have to take it off to refill the MC after bleeding each corner, but that's a minor inconvenience considering the frequency of use.  Heck of a lot cheaper than a Motive system.