Can my wife join me in Thailand under a retirement extension if I'm over 50?

IF you entered on the 60 day tourist visa, and then went right onto amnesty AT THIS TIME <- meaning right now, you cannot apply for a 90 day in country Non-O visa based on being over 50 (retirement).

That is because you need hard stamp days left in your passport.

IF you didn't get any extension on your 60 day entry stamp you MIGHT be able to go to the immigration office and apply for a 30 day 'regular' extension for 1900baht that would give you a "hard stamp"

Then you could then apply for the Non-O visa by showing you transferred 800K baht into a thai bank account in your name only from overseas.

You would apply for the 90 day non-O visa for 2000baht at Chaengwattana counter C-1 <- the counter that ISSUES in country visas.

The application would go under consideration for 14 days and then you'd go back and get the Non-O visa and a new 90 day stamp inked into your passport.

Then you would wait until you had 30 days or less left on that 90 day stamp and apply for the yearly extension based on retirement for 1900baht by showing the 800K baht was in your bank account for the previous 2 months and submitting the documentation

Okay how about stating what type of entry stamp you and your wife are on since the country locked down at the end of March?

she can get a dependent visa based on yr retirement visa under she reaches 50

Some call this a "trailing" visa. Yes it is possible. However I'm not sure how long it'll be before it's considered again post-corona.

haha, also same situation

Yes, can do.