""1) Broken starter Brass/bronze terminal protruding out the side of the starter that I believe was the type with a right angled lug to bolt the cable to (lug broken off).
5) A spring loaded "holdin" pushbutton switch near the pony controls which has one terminal grounded... and the other coming from the vacinity of the mag (small gage wire). I assume this to be a mag ground/stop switch... for the pony.""
This is indeed what you say, a Mag stop switch, but it originally was the starter button for a relay that was between the battery cable and the terminal on the starter you repaired. That was connected with a solid copper strap. The other option as was mentioned and you proposed is a high amperage manual pushbutton that also fastened onto the starter. Either one would support the battery cable and since they mount firmly to the starter case, should keep your delicate terminal repair going for a long long time. I would guess the relay is more commonly available than the manual switch.
""2) A single wire from the regulator coming around the back of the main engine and not connected to anything... but does have an eye connetor. Lug on the regulator is unreadable... I also do not understnd how these old box sytle regulators are wired either. Really do need to figure that out someday...""
If you consider the generator and regulator together as one unit, there's only one wire to the machine, the wire from the regulator BAT terminal to the battery. This wire would have been attached to the ammeter on the battery box and another shorter wire from the other side of the ammeter to the battery post. You can do without the ammeter unless you just want one and just connect the wire to the battery cable. If you have an ammeter, any electrical loads like lights etc should be connected on the regulator side of the ammeter, not the battery side. This will make the ammeter show only battery charging/discharging amps, not total generator output.
Removing the screws in the lugs on the regulator will uncover the label stamped into the terminal, but usually the BAT is on the left, GEN or ARM in the center and FLD (field) on the right. The generator terminals should be labeled Field and Armature on the case next to the studs.
""Oh and another quick question.... I assume the small valve on the lower left side of the pony's block( not the head) (as one stands next to the cat to operate the pony engagement) is the fuel shutoff for the pony?""
Yes, that's right. Like SJ says, turn off the fuel and let it run dry to stop the engine. No real need for a mag kill switch on a pony motor, but CAT had a "twist" on/off switch on all of them. Just something to forget to turn on in my opinion.
D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time:D