I rebuild F/M mags, so I'll try to answer your questions in simple terms for ya.
1.Yes, the magnetic rotor is what you're calling the amature. It's not really an armature. Main shaft would be a little better reference name.
2.The neutral point is when you turn the mag. rotor shaft real slow at the spot you don't feel the drag anymore that's what he's calling the neutral spot. If you turn it slowly a few times you'll feel that drag, then it will turn easy for a second.
3. The F/M mag caps are pretty tough. If the high tension terminals aren't round anymore, or one of them is 1/2 of what it's supposed to be, I usually replace them. As long as they are still pretty round and have their shape, the cap's good to go.
4. Remagnetising a rotor is something you don't have to worry about. You have to have a magnetizer to do it correctly.
5.6. Again, a distributor machine is needed to do testing for distributors and magneto's. Here's how you can do it home. Set the points manually (.020) and start from there. Turn the lights off and turn the snap coupler and take a look at the spark at the points. A nice bluish white spark is what yer' lookin for. You can adjust the points a little tighter to get the spark you want. Depending on the wear on the rotor cam, will determine the best spark at the point contacts. You may wind up with .018 for optimum flash. Coils usually stay around a long time. The condensor is the little bugger that causes problems sometimes. Hope this helps ya out.
Steve/B&B Custom Circuits