As for the Mamiya, get either some "stove paint" at the hardware store, or Krylon Ultraflat black spray paint. If you get the Krylon, spray some into a can and brush it on where the flocking is missing, Stove paint is the kind of paint that they used to use to paint old-fashioned pot-bellied wood stoves with. Both are extremely flat, stick really tight, and work very well for flocking a camera.
As for the magenta tint: You were getting that with Kodachrome? I'm having trouble imaging that, since it was one of the most reliably accurate films ever made. I'd be more apt to attribute that to a poor coating on your lens than to the film. You didn't get one of those crappy lenses with the red lens coating back then did you?