Not Pattaya, but I went to my local Kasikorn-branch today and opened a couple of accounts. While I have a extension of stay based on marriage so there was no problems, I asked about what about people with "regular" 90 day Non-O stamps.
The lady said it should not be a problem and sounded surprised when I told her I read about many people struggling to open accounts with their 90 day Non-O stamps.
I did that last year, but I had brought with me all the documents proving I was getting married to my now husband and needed some extra time because my extension of stay was finished before we could get everything sorted.
Then you ow know the requirements are the same to get the actual visa. Both inside and outside Thailand. Just outside Thailand you don't have to have the funds/income to Thai bank account.
The requirements are the same as the extension. But yo can use bank statements or proof of income accepted by the embassy in the country you apply in.
For Non-O based on marriage ( to Thai woman ) it's 40 000 baht a month in income, or 400 000 baht in your bank account.
For Non-O based on retirement, it's 65 000 a month in income, or 800 000 baht in your bank account.
The only difference when extending is that the money needs to be in a Thai bank account in your name. And you can only use the monthly transfers method on your second extension.
Unless you are a woman married to a Thai man. No financial requirements there for extensions at least. Not sure how they do it when you apply for the visa outside of Thailand for that one.
But likely not relevant to the OP anyway.
But all other versions of the Non-O visa has some sort of financial requirement.
E-Visa only, but you may need to attend a interview at the embassy in the country you are applying from.
Bank statements from the bank should be enough, can't imagine they'll call up the bank and ask for the information. Not even sure if the bank is allowed to give out that kind of information.
You will need to show proof of either employment or self-employment.