Shiny Locked Legendaries?

Hiya! I've beaten Z A on Eden (android), I'm now shiny hunting for the Dex - I know the legendaries are locked.

But if I were to set an encounter code (say Yveltal) and every Pokémon spawned as Yveltal, would those also be locked or could I hunt them for shinies? If not, is there a code to remove the locks? I want to get them from genuine effort rather than just spawning them in shiny lol.

Cheers!