Note: This game is also titled Gyakuten Kenji.
In Case 2, you can find Sal Manella after reaching the airport. Talk to him, and he will talk about various Internet references. In Case 3, go back along the bridge at the entrance to the park just before you go to the stage. Phoenix Wright, Maya, and Pearl will be in a boat in the water. In Case 5, immediately after you exit Theatrum Neutralis, move all the way to the right to see Lotta Hart looking out the window.