on the engine I would make a contingency plan with your buddy stating that if the engine doesn't have certain pressure in all the cylinders you can return it, or get some money back, or he fixes it for you, something along those lines, preferably in writing
was there any oil in that thing at all as it sat for 5 years I doubt it, it was just probably coated with something, there was probably no carb on it either, so I would be concerned about the intake / exhaust valves on the cylinder that were opened depending on what stroke / firing order it was on, the rings and cylinder walls may have had some sort of moisture / condensation on them, you may wanna find out by taking the spark plugs out and feeling for the piston, then when you test for pressure those may be the runts of the litter
just trying to help, hope all turns out though