This covers work - study - retirement i found this out today in chiang mai ran into an older couple here in chiang mai the husband and wife are both 50 but the wife didnt meet the income requirements on her own - untill today I thoight the same thing
There is an option non-o family visa using marriage certificate - if one of the you gets a DTV the family can accompany on a 90 day visa or visa exempt and apply for non-o family visa in thailand. Will need marriage certificate and other documents to show dependant status - children over 20 do not qualify for this
Savings will do it the income is incase you dont have the 500k baht saved up fully and you have the income to off set it - most people just do the savings amount income verification deals with alot more steps and paperwork