Evil Spirit Armor can be received after completing the Side Quest "Lomei Prophecy". First go to Lomei Labyrinth Island and activate the Side Quest, then complete the maze. When you defeat the Flux Construct (Hard), and complete the quest.
How To Get Phantom Ganon Armor Back
Available From The Bargainer Statue In Depths
Once the Phantom Ganon Armor is obtained, it will be available in the Bargainer Statue lineup in Depths, and can be reobtained in exchange for Poes. The Bargainer Statue lineup will be restocked during the Blood Moon, so as long as you have Poe, you can get it over and over again.