I had a legitimate Thai school Ed visa. No verification was ever asked from school other than writing down my address on the application forms. Immigration of course requires tm30 receipt.
I can't think of any legitimate purpose that information would be needed, even if you had an agent.
The 7 day stamp is denied extension. It is to get out of the country, in general you can't do anything to change that, you have to leave.
You can try a border run. Leave the country and try to reenter on new stamp/visa, but if you abused the covid extension you might be questioned or even denied entry.
What you want doesn't exist. To offer an Ed visa the school and you must be approved by the ministry of education for a specific program...not just anything.
The closest you could come to attending a university as degree seeking student and taking different elective courses.
I just applied for elite.. Too young for retirement visa (which seems a bit of hassle anyways).. And don't want to deal illegal visa or other requirements. If you do the 20 years, the cost isn't much as a per year fee... Just have to pay lump sum.
The deductible does not matter. As long as the coverage amount and coverage is correct. They also need to supply a document that will be easy to read so they accept...basically a single page with all the requirements listed.
They won't look at a complex policy document to verify it meets the requirements or not.
If your home country does e-visa, you can apply from anywhere... A few people have done it. Just apply online meeting all the requirements... Some documents may be hard to do remotely like background check...
If you are issued the evisa, you will still need to do a visa run to switch to it, completing all the entry requirements again.
Should be fairly easy to open an account on ED. Most branches will want passport, resident certificates (immigration or your embassy), and a letter from your school. It's always hit or miss, but most should accept you with that paperwork. SCB would be difficult, Bangkok Bank probably the easiest (even on tourist visa). K Bank considered the best and have the most atms in bkk. I am krungthai, opened on Ed, pretty happy with them... Their branches are not as busy at k Bank, but fewer atms, but I can use atm fee free so no big deal.