Just a few more items...
CIF is Catch in Focus or Trap Focus -
Photography Rulez: Focus Trap or Catch In Focus
Leitax will convert the lens for you also. I have no idea if they provide quantity discounts on ordering multiple mounts, as that may be something of interest to inquire about. The screw heads appear to be not Phillips, but JIS - Japanese Industrial Standard. Also, at least one of the screws on the mount is glued in. I read somewhere that touching the head with a soldering iron should help. Leitax is now starting to have some links to converting zoom lenses. I don't know if you have all primes or a variety.
Here in the US, the wide angle Contax lenses, 25, 21 and 18mm are extremely expensive. 28 and 85mm - at least in the f2.8 version are pretty reasonable in price. Also, the faster aperture lenses are also expensive.