I'll jump back in.

The tach bouncing is a good sign, it means that the crankshaft sensor is picking something up. However, it may be weak, but leave it for now. At least it is reading something.

I, however, had exactly that feedback when my car wouldn't start and it still ended up being the coil pack. Fortunately when I was wrenching professionally I never had as weird a case as my own car.

Did you take the coil pack apart with the Torx screws that hold it together? There are contacts in there too if you didn't find them already and they generate their own corrosion.

Actually, when I was dianosing it, I was kind of laughing because it just figured I would lend my mother something that worked fine for me for years, and it would crap out. I was joking with the owner of the shop, saying "Well, the coil IS made in France..." And it turned out to be the problem.

However it is not necessarily that problem, but it is a possibility. A good one.
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CH, reassigned to Lexington, KY