The plot thickens. If this Scout is truly a '72 model and not a '75 or '76 masquerading as a '72, then what happened is some prior owner swapped out the original points distributor in favor of this GB setup from a later year Scout. The GB setup is a primitive electronic ignition system that came along in the mid-70's and lasted for a couple years before thankfully being phased out in favor of the more advanced Prestolite electronic ignition system in the late 70's. At the risk of redundancy and overstating, a '72 would have originally had a breaker points distributor, which is obviously long gone now. So this would explain why the factory resistor wire that originally fed power to the coil has been cut off short at the BHC plug. It's the wire with the odd, cloth sleeve over the yellow insulation and now has a blue plastic blade connector crimped on.
If the fusible link hasn't already blown, then it's still good and can be kept in place. It's a good safety measure. If it has blown, you can get replacements just like it at a parts store. I think that yellow wing on it is a color code. You would want to use one that is the same rating or wire gauge as that one is. If it has continuity on both ends, then it's still good.
The starter spinning without cranking the engine often indicates a sticking bendix drive in the starter motor. It's basically a sliding gear that meshes with the flywheel to rotate the engine over and then unmeshes once the key is released. The starter motor doesn't just stop instantly once you release the key. It takes several seconds to wind down to a stop. That's why you need that gear to mesh and then unmesh once the engine has barked off so that the starter drive doesn't stay meshed with the flywheel while the engine is running. If that gear isn't meshing with the flywheel, then the motor won't rotate the engine over. I know you say you put a "new" starter on, but are you sure it wasn't just a cheap reman? Reman stuff is often junk right out of the box these days. Hopefully you didn't surrender the orignal starter as a core. You'd likely be better off with a new solenoid mounted to the old starter. A truly new starter is going to cost a good bit more than an el cheapo reman will.