Stalking this thread...anyways...Brief Explanation of the void:
A villager is put into the void when they aren't adopted.
I believe there is a max of 3 villagers in the void.
Your main street will fill up with the latest 16 move-outs (minus the void I believe)
However, those villagers are
not in the void.
Once you street pass someone/someone visiting your town/vice-versa it will clear your void - it is random who moves into the town that gets the voided villager.
It does clear the void when you visit someone who has 10 villagers.
If you don't have your wi-fi switch on and you know for sure that there is only one villager in your void most likely the next town you visit or whoever visits you that has >9 villagers they will get the voided villager. It has happened to me on several accounts when I clear my voids in my cycle towns.
Btw --> TT forward any amount of time will equal the amount of time traveled forward aka 3 days in the future = 3 days that have passed
TT backward 5 days into the past = 1 day that has passed. I can verify that.
Here is the in-detail explanation by someone else! Very useful.