You can create an account and apply for a Non O visa for the purpose of retirement, then once you have a 90 day visa, opening a bank account is much easier when you arrive.
here are the requirements for converting from tourist visa to Non O whilst in country but it is slightly different when you apply from your home country
Why not just apply for 90 day Non O visa in your home country, and then if you feel like you want to stay, open a bank account, put the funds in (800k) and extend for a year, that would be the cheapest route. I started with an ED visa and wished I went the Non O route from the start, much less hassle than TV and ED visa.