[TexasLS1]

Nice update!!

I don't have any real suggestions in regards to the security system, it sounds like someone wired in a rat's nest! I did have a 2001 Camaro SS prior to my current '72 C10 (man I miss that car :/ ), and I was having an issue similar to yours -- turn the key on and lights/dash/relays would flash and go berserk, but it would not start. I thought for sure it was the VATS or a bad key or the factory security system bugging out. I figured out it was actually a bad battery connection. The terminals were tight and appeared clean, but the side-post battery had actually leaked acid into the battery cable, so I could not see the severe corrosion inside until I actually cut away the cable's jacket/insulation. I actually got the car home by pouring water onto and into the positive cable, which helped create continuity I guess?

Sorry for the long story, but you might check the battery cables for internal corrosion, although yours sounds more like it has something to do with allllll that glorious wiring spliced in