yes, however I guess that the embassy or consulate which proceeds the application, might ask you for a proof that you are presently in their country of diplomatic residence
really? And they are switching to the E-visa system by October 8? Or maybe you are able to visit physically until the end of October. If I was you, I would inquire by email
CAUTION . . . . be aware that all of Thailand's neighbour countries are switching from physical visa-application to the online E-visa system. I guess you cannot get an appointment from the Vientiane Thai embassy any more to this day. Same applies to Kuala Lumpur: they have stopped issung appointments and they don't serve walk-ins any more. The E-visa system is supposed to be introduced by October 8
Once issued a 90-days Non-Imm-O retirement visa, you can apply for the "1-year extension of stay permit" as soon as the minimum of 800.000.- THB deposit has seasoned inside your Thai bank account for 2 months. The application fee is 1900.- THB. Some people and Thai Immigration in very bad English call the "1-year extended stay permit" a "retirement visa", however this is NOT a visa at all, this is just a simple stay permit based on being over 50/retired. The stamp tells it all, the stamp says "extension of stay permitted until" and a date 1 year away from the day after the original 90-days Non-imm-visa expired
for the application to the "change of visa type" inside Thailand, from a tourist visa or visa-exempt entry to a 90-days Non-imm-O retirement visa, either a minimum of 800.000.- THB needs to sit in a Thai bank account and there must be a proof that the money came from abroad, or one can prove by an embassy legalized "affidavit of income" monthly earnings of minimum 65.000.- THB. In order to be able to apply, there needs to be a minimum of 15 days left on the current stay permit. The application fee is 2000.- THB, and the applicant must have a rental contract, and needs to be TM30 registered.
you will need to invalidate your existing stay permit based on being married to a Thai wife, before you can apply for a new visa. You cannot have two visa or stay permits at the same time. The easiest way to invalidate your Non-Imm-O marriage visa (you probably don't have a visa at all but are on the "one-year extension of stay based on being married to a thai wife") is to exit Thailand WITHOUT a re-entry permit
you don't need any extra informations - the law says that EVERY foreigner who stays inside Thailand longer than 90 consecutive days, has to do the 90-days report. This law is completely independent from any visa catagory, it doesn't matter which visa or which stay permit you are on.