The "shiny mark" happens regularly when a shiny Pokemon comes out of it's Pokeball. As for the "Pink Pokeball" I don't know what it is. If you are talking about this -> , then that is the Pokerus cured sign, but it doesn't appear when a Pokemon is sent out to battle, it appears in the Pokemon's summary. If you are talking about this -> being the shiny mark you are talking about the Pokemon's summary.
If your Gardevoir has beaten Master Rank for all five Contest Spectacular types, when you send it out to battle, a pink ribbon will appear when it comes out of it's Pokeball.
>If you manage to win Master Rank Contest in all five types with a single Pokémon, then it's very special. This Pokémon will get given a special ribbon known as the Contest Star Ribon.
But that's not all. When you send this Pokémon out into battle afterwards, it has got a special animation which shows a shine and a faint ribbon over it, proving that it truly is a Contest Star.
Hopefully that explains it better than I can.
Also, some of the credit for this answer goes to SapphireDiancie for reminding me about the pink ribbon.
Hope I helped!