The 70% herd immunity is old thinking. With the delta variant it needs to be 85% fully vaccinated. And that should be 85% of the ENTIRE population. Almost impossible to achieve. I think they will start to open bars and nightlife once they have vaccinated 70-75% of people. For a month or so things will be ok and then problems will rise slowly. Then there will be a major outbreak which they will say they have contained. Then they will realise they haven’t and a much wider shut down of nightlife will take place. Unless you have a reason to holiday in Thailand then don’t bother. If, dare I say, you are looking to party and enjoy the adult entertainment on offer in Thailand, then I’d suggest forgetting it until at least June 2022 or later. Sorry but I think that’s the reality of the situation.
Doesn't matter. If you have a VE you get stamped in for 45 (30 again soon???) days and you have to have 30 days of coverage. A TV gets you 60 days so you need 2 months of coverage. If you come in on a new Non-O (retirement) you'll be stamped in for 90 days so have to have that much coverage. If you have an O-A or Non-O giving you a year's entry then you need a year's policy. It's tricky right now and could get expensive if you make the wrong choice.
I also found out more about the required return flight. According to TAT's Phuket Sandbox General Information page: "If the length of stay is less than 14 nights, travellers must also present a confirmed flight ticket out of Thailand."