I would suggest you look at the limited number of approved insurers mentioned on the e visa website as an example AXA are one of the approved insurers, you can get a quote online and they will provide you with the appropriate certificate for your visa
As Brandon has already mentioned there in no 12 month non O multi entry visa. However there is a non O-A visa that is multi entry for the first 12 months and can be extended 12 months as a single entry. This does have an insurance requirement from an approved insurance company as well as a police check and health check. You don't need money in a thai bank, it can be in your home bank, it still needs to have 800k baht equivalent or 65k baht monthly equivalent. If you plan to stay longer term it's easier getting a 90 day non o as Brandon has suggested
most country are visa exempt for 60 days currently, suggestions are that this may reduce to 30 days at some point in the future. The 60 days can be extended for another 30 days at a local immigration office
you may well be correct but it doesn't really matter, the only thing that matters is what the thai authorities consider. So in this instance just use your passport country of origin otherwise at present they won't let you in
it looks like that could be true as its typically when you enter thailand but until the rules have been released and we can all see what the expectations are it's hard to say. You wont need it this time on your way in but just keep an eye out when you are in phuket