I see people posting about "voiding" a lot, but i was under the assumption that in new horizons villagers that move out without a clear home enter a wait-list to move into your friend's towns. Is it still possible for them to be voided?

In ACNH the void doesn't get cleared like it did in ACNL.
In ACNL players with a a mover cleared their void by visiting a town with 10 villagers.  That villager cleared the void and the town with 10 villagers didn't get stuck with them.

In ACNH an island the void is a mess.  An island with a void can or might give it to a full island when they visit. The void can stay with the 10 full island until they have a mover and it doesn't get filled by an amiibo or mystery island.

I have 2 islands.  Island 2 Kody moved out.  Island 1 had a mover request the next day.  Both islands stayed away from each other until the spots were full.  Islands started visiting each other again thinking it would clear the void.  I was wrong.
Three moveouts on Island 2 and Island 2 got stuck with Island 1 first mover.  It was 2 weeks after Island 1 voided Stu.
About a month later after Island 1 had 2 movers Kody from Island 1 moved in.
Nintendo needs to fix the void problem if they want to sell another console/game to customers.
Posters are getting stuck with their other island villagers.

What he said. I've got a few screen shots of villagers who were in my void from previous trades I've done. I sometimes encounter an amiibo card I can't use because they are in a permanent traveling to my island state until I get someone to move out and open a space.