Knowing what I know about the previous owner and some of the other hack jobs I've discovered so far, I'm going to go with choice (B): They were just being dumb and hacking wires without any understanding of what they were doing.

 

Chasing down wiring/electrical gremlins is one of the most frustrating things. Hope you get the parasitic draw sorted out!

 

Still working on the parasitic draw, but did solve one of the minor mysteries. Installed a fuse in the "Start Signal" slot and now the little "ding ding" comes on when the key is inserted into the ignition. So it does what it describes.

Also soldered the broken green wire back together, and now the little security system LED on top of the dash operates.

Getting there a little at a time.

 

Parasitic drains can be a pain to locate without the proper tools. Do some searching for an "Amp Hound" great tool to have when locating parasitic drains. One I have yet to acquire as I have yet to encounter this type of issue on any of my vehicles (knock on wood). But I will buy one should the need arise.
Cheers!
-Icer

 

Yes, I have one of those I rented from O'Reilly. It worked great to locate the fuses where the draw is coming from. (I'm away from home for a couple days and I cant recall the exact fuses right now) I'll post the locations when I get back home. I showed a total draw of 240-250ma at the battery with the head unit still in there. After removing it I still had draws at 3-4 fuses. One was a whopping 120MA, and the others were 10 or 20. The big one fed a bunch of things, including the theft security system. I'll provide more info once I get home and hopefully can get some insight into how to proceed next.

Thanks again!