Is there any way to check the regular player numbers on the NW module specifically?
Do we know how many unique players are still active?
If not, is there anyone who has the slightest idea how many that could be?
No there's no way to tell. Educated guestimates are that the regular peak player numbers can be anywhere between 600-1000 depending on the day itself, Sunday being the higher peak.
Unique player per day numbers between 1200-2000 once you include pub servers etc.
This is only including EU and NA, maybe also SA as well. Oceana and Chinese regions don't use FSE or interact with our community so can't factor them in.
For comparison, BCoF is averaging 300-400 at peak. In May, it only went above once to 800 for the first Napoleon Event on Sunday. Gone back down to 300-400 again. Warband overall averages 4k players at all times, peaking upto 6k-7k
EDIT: FYI I am being conservative with the NW numbers so it could absolutely be higher. But regularly you can get 4-5 full servers on a Sunday which is immediately 800-1k players. Wouldn't be a stretch to say theres more.