Frank, The best thing for you to do would be to write down, then post what your intentions for this motorcycle are. Like will you ride it daily, rarely, show only...etc. Also do you want it to be totally original ? Battery, or Batteryless ? If its a 65 it has the wrong h/l bucket on it for example. depending on many factors you can go many different directions. Jim eluded to some previous write ups by bob and others on this subject. But the reason I am saying this is because, for example, if you just want to do the most with what you have, keep it 6 volt, use the aprilia key switch you have (very rare part by the way) and you arent worried about it being "all original" you really dont need to spend much money, you can buy rectifiers from many sources, this is what i bought.
www.newark.compart # 06M7446
You also do not need the terminal strip/board that you are missing in the headlamp, but if you really want it, domiracer sells it, but they have them listed under the wrong number, they have a big box of them...
On the stator, you will probably need to remove it to replace the wiring, bob could guide you through testing it, but honestly its probably no mistake that its unhooked, it probably needs the wiring replaced... If you do remove it for repair, make sure you identify if its a 28w, or 40w model.
Your in Australia already, so you could even remove it, and send it to road and race, to swap it for a rewound unit, with a aftermarket (honda type) regulator/rectifier if you so desire.
(page 32, road and race catalog)
reproduction ignition coils can be purchased from domiracer, and many other sources. same with bulbs, and warning lights.
On the headlamp itself, if you want to go the cheap route you can use a sealed beam, just a different one, but if you really are set on buying a reflector, bulb holder, lens, and lens seal it can get very pricey. one tip is domi racer sells the cev 130mm bulb holders cheap, but they are out of the reflectors. the cev parts will fit the aprilia housing, and are usually cheaper, if you can find them.
The aprilia 59n headlamp switch that mounts on the bars is ungodly expensive if you can even find one, so if yours is missing, i would either use something different all together, like a cev period correct switch, or a reproduction aprilia switch like the later widecase ducatis use (available at domiracer/eurojamb/guzzino/etc...)
I think you have the tailight covered, if not they can be found for guzzi's aermacchi's etc, sometimes with the wrong lens. but the same lamp housing...
The small terminal strips ( mounted on the frame near the battery tray 3-terminal type, and on the rear fender for the brake lamp 2-terminal type, can be found almost anywhere, even home depot or any hardware store...but a lot of times they are white, and you want black ones...they come in a long strip usually and you cut off what you need...
The original brake lamp switch can be found, if yours is missing, but if you are not worried about originality, you can find cev switches meant for a benelli i think fairly cheap. hopefully you have the original one, there are a few types, normally open, normally closed, widecase, narrowcase, etc...
thats about it, there really isnt that much to the electrics on the scrambler you have.
but like i said, if you post what your intentions are, you can get more specific info on here, as to exactly what parts you need, and how to hook everything up and terminate your connections...
All that said...If you want it as simple as possible, you could run no battery, no rectifier, an a/c coil, factory type bulbs, and a simple headlamp switch. If it is a 65, thats all it would have had from the factory anyway, it also would not have had that keyswitch you have pictured.
You may want to consider pulling the ignition points plate off also, to see if it has the AA367B (for batteryless ignition) , or the AA359 advance unit (for battery ignition) you might even find someone removed the weights, and set it up for full advance (locked)
Hope you arent to confused yet, and this helps...
Joe