Any world wide travel insurance is acceptable . Doesn't have to be a Thai based company. I use my Revolut card travel insurance. Valid upto 90 days of travel. Use a comparison site to find best for you. Or if you want Thai insurance, contact
You can apply up to 3 months before travel for an evisa. TR60. Gives you 60 days when you arrive which you can extend for 30 more at any Thai immigration office