I have often found solace in the zen of a complete tune-up. I know it sounds silly at this point, but the routine of doing all the steps in a logical order has often been enough to either correct a problem or allow me to actually see what went wrong or the proper place to extend further searches.

Insofar as the rings sealing are concerned, it would still run but would be a major dog on power (I'm reminded of the triumph with no rings at all...).

Grungy oil would be hurt the motor and it's systems not at all (except not burning and plugging the fuel filter). Since you have nice wet plugs (and it wouldn't fire on ether) it MUST now be a spark issue.

Even with the improper order of wires you should be getting "sneezes" at least, if there is any spark.

Unless there were some pretty violent backfires when the oil overwhelmed the induction system, I can't imagine that causing an ignition issue. Coincidence or accidental contact when trying to get the kaka out? Dunno, don't matter. I hope some relaxation and a revisit of the ignitin system will yield blissful noise.

Mike!