The weird C/Bs you removed were most likely smoked by the bad neutral.
The weird breakers are most likely the circuits that have single phase hot-to-neutral loads on them right now. I bet if any loads were disconnected the idle voltage would remain stable with those breakers on too.
I think a loop impedance tester would be seriously handy here. Keep measuring from the panel towards the meter and as soon as loop impedance drops dramatically you're past the fault.
