some Immigrations accept copies of the landlord's ID card front and back, and a copy of the blue housebook, signed by the landlord in blue ink. Best way is the landlord visits Immigration together with you
we never know, because many landlords avoid doing the TM30, in order so they don't have to pay tax on their rental income. In case he didn't do it, check into a hotel, ask them for the screenshot or printout of the TM30 registration and take this to Immigration (stay in the hotel until an extension has been issued)
there is no more 365-days multi entry retirement visa any more since October 2023. Surely you must mean you are on the 12-months extended stay permit based on retirement, for which you bought a multi re-entry permit for 3800 Baht. You don't have a "visa". You got a "1-year stay permit"
You have no clue! Myself I know exactly how this process is like. . . . . Applicants will get documents (faked!) from a school, enabling them to exit Thailand and apply for the Non-Imm-ED Visa, then re-enter, get a bank account opened, then do another border run, invalidating the ED stay permit, then apply for the conversion of the visa-exempt entry to the initial 90-days Non-Imm-O Retirement Visa. All this is completely unneccessary and much too expensive. It is easier and cheaper to exit Thailand and apply for a 90-days Non-Imm-O Retirement Visa outside of Thailand. Enter on this visa and get a bank account opened in no time. Agents take 5000 THB for this service
that's the downside when you don't use an agent. Agents pay bribery money to Immigration officers so they look the other way and ignore that you don't fulfill all the requirements.
the landlord must register you by the TM30 system in the house within 24 hours of your arrival in the accomodation. Having a rental contract for a house doesn't cut any ice when applying for the 1-year Extension. However you need to be properly registered in this accomodation, or Immigration will not service you. The fine for a late or forgotten TM30 is 2000 Baht
Warin Chamrap next to Ubon Ratchathani is no touristic area. I reckon you but would have been successful in Bangkok or Pattaya. The situation right now since February has extensively changed.