The maximum withdrawal amount is fixed by the bank and depends when and where you are using the ATM i.e whether Nationaly or Internationally.
It’s a random code that’s that contains 1-6 numbers and letters that gets generated by a Wells Fargo banker to confirm their identity and that the account that’s being serviced gets validated & opened
You can have a box of checks printed anywhere. You do not have to use banks provider. As long as they have the routing/acct no etc they'll work, Wal Mart sells checks online too-good for any bank