Sorry for veering the thread off into cold O2 mitigation discussions, it doesn't appear that was the likely culprit.
Making good beer should be attainable with some fixes. It looks like you are taking good steps to address the problem.
It's when you are chasing the best beer that all the other stuff down the rabbit hole comes into play (and for some people that's part of the fun)
I'm honestly just super stoked at how many people showed up to help. This is all extremely useful knowledge. Plus, I would imagine that reducing oxidation to such a degree as mentioned here will greatly prolong the life and quality of a beer (assuming I don't smash it first).