2000 Volkswagen Jetta Smog failed -OBD Communication Failur

I'd GREATLY appreciate any feedback you all might have with any or all of these issues and what may need replacing (I really can't afford the dealership fees at VW!) I'm mainly concerned about the smog and oil pan issue, but all are of concern.

Shortly after purchasing my Jetta, I began having an issue where once I turned on the windshield wipers, every few minutes and sometimes seconds, all panel lights would come on and speedometer would go all the way down to 0, etc as everything was shutting down, but car would still run, and everything would come back up within seconds. That is one concern, though I've since passed a smog and changed battery with that issue still happening.
None of my warning dash lights are on, and I haven't put in any after market equipment, but was told when I went to be smogged this time, my stereo is being read as after market when its stock and the same one as when I passed in years previous.
There was also a period my car alarm would go off for no reason, and after a few months, that stopped.

I originally had an FOB remote which was lost so then whenever I'd open the drivers door, the alarm would go off for a short period. I was able to have a chipped key without remote made (cheaper), via the dealership and eventually, when I opened my car door, the alarm just wouldn't go off at all as it remains today. Then my trunk went through a period of popping open randomly as I was driving unless I locked it on the panel the button is on w/the gas door button.

I need to have my oil pan either retapped or replaced since Jiffy Lube stripped the plug and it's been a slow leak even with an oversized plug in it. Whew! Any help would be appreciated.