Not advocating for or against the fed or advocating for or against crypto currency but instead attempting to answer your three main questions.
> What do you think the Fed was attempting to do?
The Fed was attempting to save a system from complete collapse.
> it sounds like you are advocating there be no way for an agency of a democratic government to dynamically adjust money supply (or interest rates)
This is the crux of the problem. Modern societies need currency and yet the management of the supply of that currency that is equitable to all participants remains illusive.
> Say north korea suddenly waged total was on US, or a massive natural disaster happens, but the government didnt have huge reserves of money to pay for defense or aid?
The government would use its existing resources, any reserves they put aside for this type of contingency or they could borrow (e.g. bonds) the necessary funds.