The consulates in the US don't require you to show the money for 3 months. The requirement is for 3 months of statements, but only the most recent one must show the required balance.
The owner of this Facebook group offers a safe entry service.
Fill out their TDAC form, and then on the 2nd page, you would select it as one of the premium options. They will then get in touch with you regarding your entry history to get you an accurate price quote. That's necessary as they have to check with their contacts at the airport before they can give a price.
Not relevant. You need to have your visa printed out, as indicated by the embassy and the e-visa system. You are leaving yourself open to being stamped in wrong if you don't hand your visa over with your passport.
You could very well have a problem. The immigration officer indicated you were spending too much time in Thailand as a tourist. Yet you have now gotten a tourist visa, which is still a tourist entry, and you plan on entering after only being gone for 2 months.
You said you don't want to apply for a retirement visa because of your family, but that makes no sense. You don't have to intend on living in Thailand to get a retirement visa. You just need to meet the embassy requirements. If you get a non-O retirement visa before you go to Thailand, you'll get a 90 day entry stamp and won't have any problems with immigration. You can then open a bank account and put the necessary funds to apply for the 1-year extension, or you can go home and spend a little time and apply for a new non-O before returning to Thailand.
You also have the option of the 1 year non-OA if you don't mind the mandatory insurance requirement.
the OA is a retirement visa so no, you cannot "convert" the OA to permanent residence. You can't convert anything to permanent residence.
One of the requirements is to work in Thailand and pay taxes for multiple years before you can even apply, and then it takes more years after that to process. How would someone on a work restricted visa work and pay taxes?
You making Permanent Residence sound so simple marks you out as knowing nothing about the process. There's a reason very, very few people have it.