I've locked more than a few zombies in a house before :)
--- but I've never tried to add more to the pile.
This actually occurred on a private server with 1 Player that I was testing...
With the wolf issue... before I exited the game to eat)
--- I was in the house for a good 10 minutes watching the z's and wolves go after each other...
--- (it was first time I had actually seen a wolf in the game... so I wanted to see what happened).
On a related but different issue...
- a couple days ago, I was standing outside of a house near a doorway
--- I used a hatchet on a z (but did not kill him)
--- I ran into the house and closed the door
--- then I watched the z literally crawl into the house... through the closed door (where I then killed him).
There seems to be a problem with entries points / doors.
Last week I was stuck in a room... even though the door was clearly (visibly) open...
--- I could open / close the door without issue (F Key)
--- I just couldn't exit the room. It's like I walked into an invisible door. A server restart fixed that issue.
Also... I've seen (visually) the lid of a Barrel be "on" (Barrel closed)... and the game was telling me the lid Barrel was open (off)
--- but I couldn't open or closed it. Again - a server restart fixed the issue.