Do I need to visit Thailand before applying for a NON-A visa and how can I open a Thai bank account?

To apply for a NON-A visa from your home country, it is indeed possible that you need to demonstrate having 800,000 THB in a Thai bank for two months, but typically, funds can be shown from a foreign bank for the application process. Visits to Thailand may be required for the account setup. The ONLY visa that necessitates showing funds present in Thailand is the OX visa; for others, including the NON-A, a bank letter from your home bank may suffice.