The airbag connectors are physically different, but the only difference to the wiring is that the earth for the airbag runs to the airbag connector on facelift, but the earth for pre-facelift goes to one of the other connectors.
If you're interested, i'd be keen to swap your facelift connectors for my pre-facelift connectors as I have facelift seats fitte din my 98 car.
As for the heating elements, now that i've got them I would never do without on leather seats. Also the only mod i've done to the car that the missus actually appreciates!
I didn't think it was that hard to find the climate control units. Try a few different breakers. If you are really struggling, all they are at the end of the day are variable resistors coupled to a relay. Pretty sure you could fabricate some up without too much hassle.