Not sure what you're talking about, every bank and account is different. My account/debit card was 50 baht a month and always had over 200k baht in it.
Probably best lol. You'll apply for a 90 day Non-O in country first. Money just has to be in the account the day you apply. Then for the 1 year extension the money has to be in the account for 60 days, you'll have plenty of time even if you need to open a new account.