Most countries have double tax agreements with Thailand, thats why you dont hear people paying I guess, however, you do need to make the report. Im going to do the report just to avoid any trouble that might follow, I dont want to get in a situation where Im asked to do it "now"
For 5, its a certificate of residency, i needed my lease, landlord passport picture ans picture of their bluebook, if i remember correct, it was long time ago, since then i have had it in my passport where they put it
I would advice to put less than 180, i did 179. No idea why they ask it. Maybe if you put 40 they grant you TR instead becausw its enough? 😅 who knows, this is thailand