Seems to be hard for you to understand. If someone meets the criteria for a DTV they can apply for it. You're talking in riddles so obviously you don't understand how it works. Never mind
The DTV is looked on as a tourist visa as it has an expiry date which cannot be extended beyond the five years. A visa, for example, the non-O retirement can be extended indefinitely until you kark it
You don't actually have a visa. You have a free entry stamp. You can go up to 30 days before the stamp expires, except in Jomtien where you must go within the last seven days
No such thing as a 60-day Visa On Arrival. I'm guessing you entered on a free entry stamp. Go to your local immigration office and get a 30-day extension. You can go anytime