It has been the same for a really long time, even before nightclub released.
Misty is not active until day 2
Ari becomes active on day 4
Maddie becomes active day 5
I do admit that you get nothing new until Bloodmoon Ari on night 12 so the girls are introduced within the first 5 nights then you get 7 nights of the girls just getting harder until the boss fight.