Whatever method you use for the 65K transfers - it must provide document proof that the money came from a Foreign Origin - Home Country. Also always transfer more than 65K to account for fluctuations in the Exchange rate
The STV Special Tourist Visa,.. first time with Visa 90 days, 1st Extension 90 more days for 1,900. 2nd Extension - 90 more days for 1,900 Baht. Total 270 days.
It probably has been stated... But for the O-A Long Stay Non Immigrant Visa - you can only apply for it in your Home Country at a Thai Embassy or Consulate... You cannot get the O-A Visa inside Thailand.
As John says - check with the local Imm. But if renting it is normal to document where you live. When I was on the Non Imm O Extension based on Retirement... I had to do what I described the three times I extended. Actually if you run into this requirement it is not that big a deal. I have never been refused by the landlords for a copy of these documents.
Bottom Line getting your Extension should be easy enough.
I believe you can... The basic 90 day non imm O is used to obtain a retirement extension. Just Deposit your 800,000 in a Thai bank account in your name only as soon as possible to start the 2 month Seasoning / aging of the account.
The TM.7 Application for for the Extension Based on Retirement is easy enough. You must make copies of every page of your passport. Have a rental agreement, with copy of the house owner's ID card and Tambian Ban (deed) Plus a map to your house. Bank Records, updated Bank Book. And a Bank letter and bank statement. All have to be very recent (day before) The bank letter basically states that the account is actually yours.