Some of those achievements might require some out of the loop thinking.
As for Titty monster, I believe that is hiding around Alex C2, the scenes that are required get replaced as you go further on. There is one earlier triggering scene about a titty monster and then the achievement itself triggers during the scene where Alex comes to talk to you about how Sami apologized. You will know it happened because Lisa calls out as to why Alex is running around the Cabin topless.
