I'm the OP. Sifting through all of this verbiage is not easy, especially when there are contradictions.
I think I can meet all the requirement, with the possibile exception of proving that my B 800,000 came from abroad.
Background: I had been on Exxtensions of Stay - Retirement for 11 yrs., but recently was unable to renew due to a lost bankbook on a closed bank account. Previously, I had no need to prove that my annual "top-up" of my bank account was done by funds transferred from abroad. I did these electronically, and have no printed statements from my Canadian bank. Because of the lost bankbook, I have no written proof from my Thai bank either.
What option(s) do I have, other than going to Immigration, pleading my case, and hoping for the best ?