Can a British person on a Non-O visa bring their spouse under 50 to Thailand from a neighboring country?

i have never seen a thai embassy or consulate issue a 90 day non-O visa based on being a trailing spouse to someone whose partner has only JUST received their own 90 day Non-O visa. There isn't a consulate in S/E asia (or anywhere I think) that will do it

The person getting the retirement Non-O has to get their year extension THEN the spouse can go get a 90 day Non-O at most of the thai consulates in the area (although all the reports of it being done are pre-covid shit show 😮 )

Bring the wife in on a single entry tourist, visa, have her take the 30 day exetnsion, that gives her 90 days and should be plenty of time for the husband to get his year extension based on retirement,

THEN

send her to a consulate and try for the 90 day Non-O (I'd say Vientiane or Savannakhet would be good choices)

So, breaking your question down (sorry, edited : one part is not clear):

-If a British passport holder can be dependent on a British passport holder?

> can

- If a person under 50 can be dependent on a Non-O Retirement visa or extension holder?

> can

- If a person can be dependent on a Non-O Retirement VISA (not extension yet)?

> Logically, possible. But we have never seen that someone has done it other than applying for both at once at the Thai consulate before flying in. If the primary foreigner is already on extension, yes he/she can.

- If a gonna-be dependent person can apply for Non-O dependent to a foreigner who is staying in Thailand legally at the Thai consulate in a neighboring country?

> Technically can. But we have not had any report someone did after Covid chaos.

Just to clear:

Is the question: Does anybody after this Covid storm applied for a new:

Non Immigrant O visa depending on husband with a Non Immigrant O visa based on over 50 years of age at a Thai Embassy in a neighbor country?

Every person has their own passport and their own visa, you can not add others on your visa, they can apply as being your dependent. (spouse)