Unfortunately most of your shiny competitive legends are hacked, legendaries from Kalos have anti-shiny measures on them so any you received have shininess hacked onto them with a PowerSave AR, Reshiram and Zekrom have anti-shiny measures as well, also the only Jirachi that can be shiny are the WISHMAKR Jirachi and the recent Tanabata (MoonBlast) Jirachis the Draco Meteor ones have anti-shiny measures as well, all 5th gen event-exclusive pokemon have anti-shiny measures as well (your Meloetta and Keldeo are hacked) aside from the Japanese Movie Genesect that came with event moves, your Regenerator Ho-Oh is hacked as well Dream Radar Pokemon have anti-shiny measures as well, only 3rd gen Deoxys can be shiny, your PLASMA Nasty Plot event one is hacked, all shiny Arceus are hacked as well all instances of it's event have anti-shiny measures, as for Diancie it cannot be shiny as well, anti-shiny measures.
overall 13 of your competitive shiny legends are hacked.