Get the non O so no insurance required. You can get travel insurance up to a year. That gives you plenty time to get here and figure out what you want to do about long term insurance.
is he talking about the initial 90 day O or OA or the 90 day and the extension? It's not clear. If he's talking about the extension also and wants to use the
I was told 500 baht when opened my first account. My second account they did not say because they knew I was depositing a few thousand baht. You may find that the requirement is different at the different banks and also different branches but it should be very minimal wherever you go