Yes you can convert your visa exemption to Non im O 90 days, and extend this 1 year. The latest you can do it is 15 days before you stamp expires. But better start before that.
No you cant but you not need be in blue book for bank accounts, you bring the blue book to immigration and get a recidence certificate, this you can use to open bank account, but you need Non im O visa.
You overthink, if the visa exemption not go back to 30 days before you come its no problem. If you want to feel more relax, you can apply for a turist visa, 60 days.
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