>>54089526Celebi is not shiny locked. Shiny locked was not really a thing until gen 5, gen 4 if you count pokewalker. Gen 1 shinies technically did not exist.
Mew can be turned shiny and "legal" with further glitching. Now I'm not talking about the "legality" of it being a glitched mon, I'm not sure if you could even get the right DV spread from the legit event.
Somethings to keep in mind.
All mons from g 1/2 come with hidden abilities.
shiny breeding in gen 2 has pretty good odds once you learn how to do it.
You CAN shiny hunt in gen 1, but only static encounters and gifted mons have the correct DV spread. So the birds, snorlax, mewtwo, eevee.