Chattering Teeth-Found in the main hall in the present; open the grate and then chase them into the hole to get them.
Disappearing Ink-Obtained in the middle room of the second floor (present).
Fake Barf-Present: Push the right hand speaker in Green's room (second floor, right room) and turn on the stereo.
Flag-Gun-Give letter from the past (mailbox) to man in present, second floor middle, then grab the gun.
Cigar-Lighter Gun-Use Flag-Gun (see above) with Cigar-Lighter Gun in the main hall (present).
Exploding Cigar-Talk to the guy in the main hall (present) after having obtained the Cigar-Lighter Gun.