okay, I was just checking you weren't applying for the non O retirement visa, because if your plan is to retire in Thailand, you need the non O visa before travelling, or you would not be able to open a bank account to extend your stay.
Apply for the non O based on retirement before you come to Thailand and you can open a bank account here. No need to use an agent, extending your stay is easy and there's no criminal checks. Good luck and enjoy.
I said 'virtually impossible ' not 'impossible'. I personally would worry about using an agent that offers to open an account on a tourist visa when the banks are closing the accounts of people that only have tourist visas, but it's up to you.
you need to get a residence certificate and medical certificate. Make an appointment at Dept of Land Transport in either ChaAm or Pranburi and do the simple vision/reaction tests to get a 2 tear Thai license. It's very easy, good luck.