The import password should be your nushares wallet password.  The wallet itself needs to be unlocked totally, not just for minting only, but this is only a problem if you encrypted your wallet.  If your nsr wallet password has spaces, you should use double quotes (") around the password.

4 bks = 40k nsr is correct.  1 BKS is all you need to vote and receive rewards.  I received a 0.01 BKS reward for my first mint, so I think they increased the reward (NSR reward is 40, which equates to 0.004 BKS)