as I said look at your home country' tax agreement with Thailand. If your scared to pay an accountant for one hour chat you haven't got enough to pay tax. Simple
it depends on your home country. If it has a tax treaty with Thailand no problems at all. Much fear mongers on social media. Best advice speak to Thai lawyers or accountants, put your mind at rest
Why not just apply for your visa through the embassy in Canberra or the Sydney consulate if a NSW resident. It's not that difficult and you can use a visa agent in Australia eg C.I.B.T visas have office in Melbourne
keep assets in NZ or Australia, just rent real estate in Thailand. So many different areas to choose to live in Thailand good to spend time in different areas to see what feels right for you.