I am not an expert as my Embassy will not issue the affidavit, but that is my understanding. Ask at your immigration what they need to accept the affidavit method.
Like I stated, you are making a really good point about the non OA, but it reads like they can only apply for the non OA from their home country (not the non O). Many people are confused about this and think that they can only get the non O when they get to Thailand and as we both know that is not true, as they can also get the non O. Opening a bank account in Thailand with a non O should not be a problem as it's a long term visa. The problems people are having are with tourist visa or visa exempt entries.
pointing out that the non OA visa is an option is a really good point, but you are part of the reason that people get so confused about which visa to choose. You can easily edit your comment by adding the word 'ALSO' in the first line, between the words "can apply" and in a few other places. I realise you will not do this because it means admitting I am correct.
I understand and only you can fully know your circumstances and what you need to be happy for the rest of your life. I too have had bad experiences with marriage with western women (as most men that come to Thailand have) and what people say is true. If you choose the right Thai woman (and you seem to have done that), they are everything you dreamed being married would be like. My wife is the most perfect woman I could have imagined; intelligent, charming, funny, positive, loving, caring, affectionate etc. Every day is filled with love and laughter and she appreciates every little thing I do. Like you stated, see how you feel after you meet and do whatever suits you, take lots of pictures together to use as evidence and then, with good organisation/presentation of evidence, she should get a tourist visa to visit you. Good luck Harry.
your post is confusing as it implies they can't get the non O in the USA and that's not true. They can also apply for the non O in the USA before coming to Thailand and avoid needing the mandatory insurance (that seems to have a sketchy reputation) and choose their own insurance company. The non O also allows them to use their funds in the USA to apply, they will need to open an account in Thailand to extend the visa, but this should be no problem as they already have long term visa.