I just recently restored/modified my fuel tank; hopefully this information helps.
Breather valve and seal: Part numbers 20241 and 20242 from
www.broncograv eyard.com [Ford part numbers E2AZ-9B593-A (valve) and E1FZ-9B076-A (seal)]
There was a shield that is installed between the gas tank and the rear axle housing. For your Bobcat, it would be Ford part number E0FZ-9B007-A. I did not find any on eBay or at Green Sales Company, though. Maybe someone on this forum will have an extra they could sell you. It's molded and slides over the passenger side gas tank strap. It's held in place by the shape of tank when the straps are secured by the captive studs under the rear bumper.
The gas tank vent valve will have a rubber hose that goes to a 1/4" hard line under the car on the driver's side; on my 1980 Runabout, this hard line runs up to the front of the vehicle's inner fender, to the carbon canister.
Fuel lines are 5/16" for the supply, and 1/4" for the return, so check your sending unit for these sizes. Ford used different part numbers for the wagon and sedan/Runabout sending units (D9FZ-9275-A is the part you want). I would suggest using copper nickel (CuNi) fuel lines, as they are corrosion resistant and easier to bend than regular or stainless steel. Just search on eBay and you can get 20-25' of tubing. I bought from eBay user motorcitymuscl
ecar.
If you haven't gotten it already, you'll need a lock ring and gasket for the sending unit.
Good luck!
-Steve