Thai citizenship group this group will give you accurate answers, lots incorrect above.

Key point on your question is are you married to a Thai?

If yes then no need to have PR, read, write or sing. Some conversational Thai will be expected but not fluency and your wife can join meeting and assist you on Thai bits.

If not married then you will need PR which is harder than citizenship to apply for, plus higher language requirements including singing the anthem.

You can do 90 day report online, but not the first one.

So do your first 90 day reports, test the next one online, then renew the passport early next year.

Info on business, non b visa and work permit here.

If you open a business all possible.

Work permit on retirement visa not possible.

Your best bet is go to labour department yourself then.

Your employment is controlled by the employer so they wont need power of attorney to cancel, not quite sure what happens if they dont have the book.

But if you no longer work there then they legally need to cancel work permit.

They legally need to give you the cancellation letter.

If you have the book then you can always go and cancel yourself, which is probably best bet

Yes work permit can be cancelled without your presence by the employer.

If you are on an extension of stay based on employment (eg. Non-B extension) then you need to go to immigration immediately after work permit is cancelled (same day) and cancel your visa, at which time you can (depending on local rules) extend your stay for 7 days (sometimes more in other locations). Else leave the country same day, which could be on a border run and return on a visa exempt entry.

This will list the visa options you are eligible for based on a few inputs.

Depending on your Thai company, a Non-B would be best legal option.

But you will need up to 4 Thai staff and 2M THB registered capital per work permit needed, if your friend is here and working too then will need double that.

If you get a valid long stay visa then your wife can follow as a dependant, no need for her to have a work permit, unless also working here.

Other option is Elite visa since it doesn't sound like you qualify for the LTR visas.

No minimum, as long as not had lots of visa exempt entries recently.

But sounds like you came off a 1 year Non-O extension so all fine.