I had a good laugh at your attempt to clarify my advice . . . . . of course I can say "you need a minimum of 30 days left on your 90-days stay permit before you can apply for the extension" . . to call it "maximum of 30 days" isn't really making any sense, because from the 30 days left you count DOWNWARD, which gives sense to the word "minimum". You could also don't say anything at all, and say "up from 30 days left of the 90-days stay permit you can apply for the extension" . . .trying to sound smart? Give it up, buddy
no, for the application to a 30-days touristic extension, the fee is 1900 Baht. . . . You CANNOT buy a 30-days extension on top of a 90-days Non-Imm-O Retirement Visa. You can only get the 90-days stay permit you got stamped when you entered Thailand, extended to 1 year, by fulfilling the financial requirements. You can, however, buy a single re-entry permit for 1000 Baht for the 90 days stay permit. A re-entry permit doesn't buy you any extra time - it only keeps the initial 90-days stay permit valid in case you exit and re-enter Thailand within this 90-days period
you could buy a single re-entry permit for 1000 THB, which would keep the 90-days stay permit active when you exit Thailand. However you need to know, at most Immigrations you cannot apply for the 12-months retirement extension unless there is a maximum of 30 days (on some Immigration up from 45 days) left on your 90-days stay permit. For the application to the "retirement extension", you need to visit Immigration personally
if you stay in the country for full 90 days, you need to report. You do the first report after having entered in person, and can do all future reports online. You have a 21 days window for reporting - 14 days before due date until 7 days after due date
her problems apparently resulted from her using an original birth certificate of her son on a Thai authority (be it an embassy or an Immigration office) These Thai authorities only accept foreign documents if they are certified (legalized) by a Thai entity. . . you are fine if you hold an original Thai birth certificate that lists you as being the mother of a "half Thai child" . . you can use it for an application to a "dependent" Non-O visa for your child
her problems apparently resulted from her using an original birth certificate of her son on a Thai authority (be it an embassy or an Immigration office) These Thai authorities only accept foreign documents if they are certified (legalized) by a Thai entity
then why do you tell us an inflated overpriced service? The agent I know in Pattaya will get you BOTH Thai drivers licenses (car & motorcycle) on any visa (even on a visa-exempt!) for 7000 THB, and a blood test is not required, I have no idea who told the OP