The current in game nations are correct as Qatar`s agreement ended with the world cup. it is also stated which countries on their competition rules, which is only written in Japanese, but clearly stated. With the Albirex Singapore agreement ending, it is possible singapore will no longer be a partner nation next season.
Foreign players do not require a work permit. I will rephrase, the work permit is basically the usual immigration rules, which are if you have enough to support yourself then you are good. all J.League players easily hit that benchmark making it not required.