I can't answer all your question but #4.

The so called lower brand "Maestro" is actually a Master Card product. In Europe it is issued by most banks as the general cash/debit card. It is actually the successor of the EC-card. The benefit of Maestro is that unlike the EC-card it is now accepted outside the EU for cash withdrawals and for paying. I don't know any Maestro card that is issued without having a checking account with the issuing bank. So Maestro is not anonymous. At least not in Europe.