I applied through Washington DC, I didn't have to show a plane ticket but they did ask for a flight number. I only showed 1 month of bank statement. I rent a condo, so that was the address I used.
I already had a doctor i was seeing in Bangkok. I just asked her to give me a letter confirming I was a patient of hers and that hospital. She put in the letter 1 appointment in December and it was approved, no questions asked. It must be on official hospital letterhead with the doctors signature. I just said I needed it for my visa, didn't mention what visa I was applying for.
No, all I submitted was the letter my doctor gave me with my info on it. It did have her name, email and of course the hospital. It was on an official hospital letterhead also.