I can confirm that you don't need status to request seat in F cabin. Flew TG466 yesterday and managed to get 1A, you just need to be proactive and get in first (pardon the pun;-).
I have long given up on the Thai website but simply called Thai reservations and they were most helpful. Catering was still J but crewed by FAs usually dedicated to F and service was excellent. Great flight all round.