It's all about your passports, not the fact you are married. You apply separately, the same as if you are not married, at the embassy of the country you want to visit.
you are just a little misguided on the different business structures available in Thailand, and the requirements. A business set up under the BOI, board of investment, structure does not require any Thai employees, except a licensed Thai accountant, and you can own 100% of the company, with zero Thai owners. There is also another option if you are an American citizen, but I won't go into that in detail, but simply saying under that the only requirement is a licensed Thai accountant, and that can even be hired part time. There's another little detail most aren't aware of when trying to set up a fake corporation just to get the long term visa extension. If the company is not making a profit within three years that corporation is dissolved by the government, and closed, ending the visa extension.
with any type O visa extension you simply get a multi-entry re-entry permit and that makes it multi-entry for that full year the extension is valid. It is that simple.
as long as you can meet the financial requirements lots of visas are possible, but to do any work, for pay, or for free, you must have a work permit, and to get that you first must have a job. That employer must also meet the financial requirement to sponsor a work permit, meaning they must have at least bt2million in registered capital, and have at least 4 Thai employees on payroll for each work permit. You can't get a work permit then find a job. It doesn't work that way legally. For the retirement visa extension you must have at least bt800,000 in the bank, and the DTV visa requires at least bt500,000 in the bank. Just a side note, if you are caught working illegally you will be deported at your expense, and banned from returning for a number of years, and people are busted all the time for working illegally. Last month 3 DJs working illegally on Koh panghon island were busted. It only takes a single complaint filed to end your dream if doing something illegal. Keep that in mind. Thailand is not cheap to be in long term. It takes a reasonable amount of money.
She is being lied to. No agent is taking anyone to court, as that costs more than a year's worth of rent. It is simply a scare tactic. She will lose her deposits, that is all that will happen.