Biometric data - not only is record in your book but finger print and eye scan holds records as well - people with a new passport book cant say they never been there thailand isnt a third world country
no - retirement visa is 1 year - what you are thinking is the 90 day non-o visa that gets extended to 1 year to apply for the retirement visa in country - 90 day non-o visa is used often for people to come in apply for a long term non-o visa such as retirement - spouse visa.
yeah untill its not easy - you can also use monthly income 65,000 instead of savings as well - if your embassy will certify the monthly income with your statements should work but they jacked the system to Crack down on fraud
It doesnt matter the source of the money as long as you can show bank statements of it and constant - im VA FnP as well - your compensation / pension will not be taxed by thailand as well - its exempt under the DTA with the US
You should be fine as long as your re-entry came from your home country and you didnt extend you should be fine - ill even bet they wont ask you for the 20,000 baht cash