The tire chains and fan should be easy to find or at least get a substitute of something reasonably functional. Even if you have to pull the shroud off and install an electric fan, or substitute a similar Kubota or Yanmar fan or hub, you'll be able to requisition a fan of one type or another.
The coupler may be tricky, but it's not unachievable. You can get chain couplers from Surplus Center, Hub City, and other places. I've had a special coupler built from a splined coupling and a piece of plate steel to fit the front of my damper pulley to power a hydraulic pump. Even if you cannot weld, it should be a simple job for any machine or fabrication shop. If you have the components up the coupler, you'll be able to get something to work.