No, you cannot soft reset for any event Pokemon to get a shiny, the only way you can get a shiny from an event is if the event is for a shiny Pokemon.
Hope this helps!
Yes, there is. Event Pokémon cannot be SR'd to be Shiny; either they are coded as normal, or they are coded as Shiny. Correct me if I'm wrong, but in all my research I did not find a single example of an event Pokémon being soft-reset as a Shiny.