What are the health insurance requirements for a Non O retirement visa extension in Thailand, and can my wife extend her stay on a tourist visa?

there is no proof of insurance required for a yearly extension based on being over 50 (retirement) from a Non-O visa.

Sadly your wife cannot get an in country Non-O visa issued based on being married to someone who is on a retirement extension because no office will issue it for that reason. She would have to get a 90 day Non-O visa before she comes here and then she could get an extension matching yours