What are the bank statement requirements for a DTV application at the Canberra consulate, and is a sponsorship letter sufficient for dependents?

I’m looking for advice on applications through the Canberra (Australia) consulate.

I have tried ringing and emailing multiple times without a satisfactory answer.

I’m hoping someone here can help.

My husband wants to apply for DTV in May. We keep our savings in 3 different bank accounts in two different banks.

I was wondering if the Canberra consulate requires the 3-6 months bank statements to show that the 500k has been sitting in one account or if we can transfer the equivalent of 500k into one account and then just provide a proof of current balance for the day the application is submitted?

Also, as dependents, is a sponsorship letter for myself and my kids sufficient or do we need to show proof of additional funds in bank accounts?

Thanks so much 🙏