There is no guarantee it will be shiny. The chance is the same as usual, 1/8192, unless the Ditto and other Pokemon are from different-language games (e.g. Japanese and English) then the chances are increased a bit.
No you can only obtain shinies in the wild or breed Masuda method.(a pokemon from a different country and your own)
How to change your username
How to add a user avatar
Why was my post hidden?
Flags vs Downvotes
Official PokemonDb League
Type a Pokemon name, type, move or ability to see instant results.