Apply for your Thai retirement Non-O Visa in Cambodia then you don't need a Thai bank account until you are planning your first 12 month extension (assuming that your Embassy does not issue the income affidavit)
When you are stamped in check the date on your stamp before walking away to ensure that it is 90 days as mistakes are made and difficult to correct later
I think you mean you will be on a 12 month Extension of Stay based on marriage which is not a Visa so you get a re-entry permit as above to maintain your statues and return in time to apply for your next Extension of Stay