I did my retirement extension December 23 in Chiang Rai. I had a map with the coordinated on it but I did not give it to them and they did not ask. Different office, different requirements . I went to my Bangkok Bank branch the morning of the 23rd a had them print out an updated statement which only had transactions through the 22nd. They also updated my bank book with an entry dated the 23rd indicated balance brought forward. I did not need to do a transaction. I also got the bank letter. With regards to the OP point 4 - copies of previous extensions, I provided a copy of all of the used pages of my passport which included a number of previous extensions. The only difference this year was that the IO asked to see my bank passbook. For proof of where I live I provided a copy of my yellow book and pink ID card.
I don’t know about other offices but I was able to make an appointment. In Chiang Rai I don’t think very many people do this because I had to ask for the supervisor because everyone else didn’t know that appointments could be made.