I'm American too, I assure you there are doctors places that will get you the forum filled out. Of all the people I've ever seen on here, never once has anyone actually gotten a test for leprosy or elephantiasis.
For the bank account, there's always a branch somewhere that will open an account for you, normally Bangkok Bank is the easiest. You'll need a letter from the US embassy called a "certificate of residency" which costs $50. Go on the embassy's website and make an appointment now, there's a long wait.
The medical certificate for the Non-OA stating you don't have the 5 diseases can be a pain, but easy enough if you find the right doctor. In Thailand, the physician asks you if you've ever had them and then signs that you don't, find one in your area to do the same.
Also, you'll need health insurance for the Non-OA. When you enter Thailand, you'll only be stamped in for the time that your health insurance is valid for.
No, you need a tm30 to get a certificate of residency.
A tm30 receipt is simply a receipt that you've been registered at an address with immigration as required by law. Everytime you stay in a hotel, a tm30 is done online for you automatically (or it should be).
A certificate of residency is a paper issued by immigration or your embassy certifying your residency status/ address in Thailand.
The entry stamp on a Non-OA needs to match your insurance. If your insurance is valid for less than 1 year then you'll only be stamped in for the period of time up until your insurance expires.
If an officer overlooked that in the past and stamped you in for a year anyway, they were wrong.
Best advice I could give is don't sell everything you own. At the very least, leave your car with a bag of clothes in the truck parked at a friends house. You'll want/need to go home eventually for a couple weeks here and there, it's so much easier if you have something there.