At the core of all your questions, you're basically making arguments for Keynesian economics while Bitcoin is more of an Austrian experiment.

Just about everyone alive has been alive inside of a Keynesian system and concepts like "deflation causes hoarding" and that makes markets collapse are Keynsian Econ 101 arguments.

Frankly, I believe we're not going to know until the experiment plays out because it's all just theory, really. Even people's interpretation of history diverges along these same lines. The different schools of thoughts will blame different motive forces for things like the great depression.

Finally, Bitcoin does have some unique features, like it's practically infinite divisibility. This allows new monetary units to be deployed without diluting the total supply with an amount of frictionlessness that we've never seen before.