If the 500k is to show enough money to support yourself over the 5 years then how can it just sit in a bank and never be used. Not everyone is applying for remote work so some are expected to have no income.
Depends where you apply. I got mine from London and only closing statement for the day I applied was needed. I transferred the full amount of money on the same day too.
I was in Thailand on ED visa then my work contract and certificate of employment for DTV states my length of employment, showing it was the whole time for my ED visa but I got approved and stamped in.