Thanks Tod. On another well known ThaiVisa forum, they're saying the opposite, as the graphic for Muang Thong only refers to Notification of Residence. I'll head to Muang Thong next week.
I know that, as my family are patiently waiting for the Laos border to open so they can come home. They need to formally confirm that commercial flights can resume too. I think more news can be expected tomorrow.