A number of factors can come into play like: how long till you leave, how busy they are, what type of visa, etc... mine was about 5 days if I recall...
not sure how you come to that conclusion. Non-o through an embassy before arriving works well. One could question the sincerity of someone entering on exempt or another visa and then deciding they want a non-o.
Not for year 1. You will need to show 800k in Thai bank account for your first extension. At your next extension you can show 12 conscetutve months of at least 65k into a Thai bank account.
The SSA statements of benefit don't mean anything to the Thai government.