Start through this area as we did before, I missed a really obvious Cobweb, sorry about that. Use the ball returns to make your way through here a lot easier. When you get to the area with the big plunger that launches you up turn around behind the ladder you came out of and you should see the Cobweb just chillin on the wall.
The vault we missed is in the room with the big fan that blows you over to the ladder. If you are facing the fan you should see a flower to the left of it and from there you can jump down to an area back against the wall and down a bit from the fan, there should be a green figment by the entrance. Inside you'll find the Vault containing the "Milla's Children" memory.
Next let's head to The Milkman Conspiracy.