Stop asking questions here and go to immigration for visa needs, I suggest to the office in Bangkok. For bank I went to Bangkok Bank on Selom Rd Bkk and then got all the info they asked for and had no problem. If you need the B800,000 and do not have that then you can't afford to get retirement so go for a different one.
I flew to Thailand on Thanksgiving day some years ago. cost less and the best part there was many empty seats so I could stretch out across the middle section of seats. I also got extra meals and 2 colas free. Fly on Christmas day if you can.
If you have at least enough savings to equal about 3 million Baht and an income to equal 60,000 Baht or more then you will be able to make the move rather easily. Thailand is a good place to live. Be sure to be of calm temperament.