Short Selling

I think this would depend on the type of mispricing. E.g., heterogeneous priors with shortselling can lead to wide swings in prices.

I would have said strongly, but there may be instances where one could use other securities to synthesize or mimic the short.

Restricted trade on one side of the market, if binding, by definition prevents matching supply with demand, and thus "fundamental" prices.
-see background information here

Even with short selling, it can be hard to stop a bubble. Without it, well...

more impt question is whether shorts produce info that improve firm governance. mandatory disclosure rules raise firm profits & stock price
-see background information here

If short selling is lawful and fraud is not prosecuted, there is a big opportunity to spread fraudulent rumors and gain by shorting.

On average definitely. By the nature of learning processes, not always.

This desperate policy does not work. See Geanakoplos for the dangers of leverage and the inability to short in producing instability.

-see background information here

Most studies that I have seen indicate that banning short selling has no effect on average price, but does lead to higher variance

Seems logical as a matter of economic theory. As a matter of practice, I don't know the relevant evidence.

Subject to the qualification of market corners.

I can imagine different scenarios, and I don't believe there is clear-cut empirical evidence.

If they have any effect, it's got to be in that direction.

I've never seen any evidence on this point.

If Bob Shiller had succeeded in making it possible to short real estate markets, some of the bubbles might have been abated.