1. Three individuals are involved in this scenario. The creator/seller of the widget. The purchaser of the widget. The bank lending money on the widget. No money was created 'out of thin air' in this transaction. The purchaser desired to own the widget but did not have the funds. He borrowed the money from a bank and gave the money to the person who created/sold the widget. The creator/seller of the widget re-deposited the money in the bank. (Simplified version of a transaction for sake of discussion). The intrinsic value is still in the widget and if the purchaser does not repay the bank, said widget is repossessed and sold. Simple circular transaction. Of course, the individuals 'promise to pay' comes into play but is in no way a 'creation of money out of thin air.'
2. Credit card usage is not creating money out of thin air either. It is a promissory transaction between the borrower and the card authorizing institution. It is purely a 'promissory note' simplified according to the agreement between the institution and the credit card holder. Again, if the cardholder reneges on his payments, the institution is free to take him to court and attach his assets. It may be a poor lending practice but it is hardly creating 'money out of thin air'. In regards to the lending practices pre 2008 for home mortgages, that too was not 'creating money out of thin air'. That was out and out fraud. Stealing money on paper and hoping not to get caught. Banks bundled too many 'junk' mortgages into derivatives and sold them at a higher 'rating'. It was a case of 'let the buyer beware'; not creating money 'out of thin air'.
3. The Wells Fargo scenario has nothing to do with this at all. Wells Fargo created false accounts for people that already had money in their banking system. What they did was move money from a depositors regular account into the new false, unauthorized account. In many cases, the original accounts became overdrawn and triggered fees that went into Wells Fargo's bottom line. No money 'was created out of thin air'. Just stolen from the depositors through fraud and added to the banks balance sheet.
The Mark Twain story is cute. But it has no bearing on reality. If the principle of the story wanted to, he could have just deposited the money and begun to conduct business with his newfound wealth.