if you've spent any time in Thailand you should know that's not how it works. Every Amphur is different, every immigration office is different, every branch of every bank is different. I could go on.
There are only 2 visas that officially allow you to work remotely from inside Thailand. One is the DTV and the other is the LTR Work from Thailand Professional visa. The latter is a lot more difficult to satisfy the requirements but has the benefit of not having to pay any tax on overseas income. Other than these visas your only option is to work illegally, people do this but you need to keep it quiet
most likely will depend where your husband will apply, no nearby countries seem to issue a dependant visa where the primary person is on retirement, others seem to want the primary person to be on a Non-OA visa. Timing may also be an issue, as in he may have more success once you are on an extension of stay rather than a visa