nothing is stored on the chip in your passport with regards to your Thai visa. Electronic visa means it’s not a physical stamp in your passport. It’s stored in the computer system but not on the chip in your passport
You just need one. Go to your local immigration they will give you the requirements for a non O in country or a one year extension if you already have a Non O issued outside Thailand
it also depends on the agent you are dealing with. So calling the airline is useless. Be ready to buy a fully refundable ticket on the spot or purchase one before and cancel after you arrive in Thailand for a full refund
for subsequent extensions on retirement it’s highly unlikely unless you’ve been rude to the immigration officer or given them some reason to be suspicious. Extensions based on marriage are a different story