Yes, the bank key is the same as the routing number for banks located in the United States. The routing number can be found on check and account statements.
Routing bank is the same as the sort code. UK banks use the sort code while the US banks use the routing number.
NO
Banks can have multiple routing numbers, but any of the routing numbers should work. This often happens as a result of mergers and acquisitions. However, the person who answered that it is different on his deposit slip is wrong. That is not the routing number but a number used by your bank to process deposits. Don't use deposit slips for getting routing numbers.
322271627. It is the same as when it was Washington Mutual.
Routing numbers are not the same as IBAN or Swift codes. IBAN codes are international bank account numbers usually used in Europe. Swift Codes are used for bank transfers, usually for international transfers. A routing number is the nine digit number used in the US to name a financial institutions.