The fact that the girl from ch 46 is now cleaning outside the room gives us a rough idea of how much time passes between debuts. Emilyko first went outside the room roughly a month to a month and a half ago. We can tell this by counting the grand cleanings (called major cleaning or cleanup by the current group) and the festivals of delight. Chapters 53 and 54 explicitly say that those activities happen once a week.
Emilyko progression: Ch 1(Emilyko introduced) ->Ch8 (first grand cleaning, first time Emilyko leaves the room)->Ch 13 lesson (Time of first ghost disturbance, appears to be a midweek activity, but could be a grand cleaning) -> Ch17 (another grand cleaning, with a speech by Barbie beforehand)-> 5 nights of patrol -> debut (appears to have taken place around the time of a grand cleaning) -> ch 53 (another GC and Emilyko's introduction to the festival of delight)->Ch 54 (Another GC/FOD, second ghost disturbance)-> ch 80 present day (Everything that went down between ch 54 and ch 80 appears to have taken under a week, but we should be close to another GC/FOD)
Ch. 67 showed us evidence of 24 separate debuts (17 debuted groups, 6 singletons, and a small group yet to debut). This suggests that Barbara and Maryrose debuted about 2 to 3 years ago (depending on how many debut groups lost all their members, much more time could have passed).
It is worth noting that neither of the 2 dolls introduced in 67 as having yet to debut are among the 3 recruited from the village in 46. While they may have been pulled from another trip, I suspect that they may have been produced naturally by the adults of the shadow house. (They have human bodies. I see no reason they could not have human children.) (The faceless dolls could be another source of children for the house, but there are some very cringeworthy implications to that idea.)