Well, Kodochakhfan, I think you are in the clear as long as the ID/OT and pokeball are correct. Most on that thread you showed us say that shinies are possible. Also, consider that the d/p pokedex on serebii.net displays a shiny version of the sprite and I don't think they'd show it if it wasn't possible. All Jirachi are from events, if shinies weren't possible they would not show us the sprite.
Anyways, the info checks out. Don't worry about the Pokerus, everyone seems to have it these days and with the gts, it spreads like a real life infection.