Heartwarming Moment - The ENTIRE Epiclouge. Yes, even the parts where Minatos threatens Metatron to stay out of his business and he crushes Izanami after the events of Persona 4 with THE ENTIRE UNIVERSE!
Not to mention chapter 94 when Minato sleeps with Mitsuru and technically has "robo-sex" with Aegis while dating Yukari who is in this story is Little Miss Weapon Wieldin' Mood Swings. And earlier in story, he did it to Chihiro and Yuko! Good thing he is also a Manipulative Bastard. He does feel guilty about it though...
Very, Very nearly Jin. The one flaw in The Plan was that he didn't account for Jun Kurosu.
Nightmare Fuel - How the author goes into GREAT detail about how Nyarlathlotep destroys most of Minato's Personae falls greatly into this trope.
When Minato gets scared, you'll know it, because the Narrator keeps narrating through the fear. It get's really bad when he's scooping his lungs up off the floor and running for his life while under Panic.