You don't need to swap the steering gear unless you are trying to cross between the flare and O-ring years.
Also, it's nice to have a pump reservoir with dual returns, but it's not absolutely necessary. You can always tee into the return line close to the pump. The P-pump inside is the same on all of them anyway, so if you have a good pump all you really need is the reservoir. But think about warranty returns if you will be swapping pump parts around and have a warranty or may get one.
I think you can still get the hoses from standard parts stores (just order parts for the 1-ton with hydroboost), but it's much cheaper to get everything from salvage and less likely you'll end up mismatched.