If you weren't aware yet, the third and final week of Ultra Bonus will start on September 16th. It is from this moment that the first Pokémon of Gen 5 will show up! Klink, Patrat and Lillipup will be available but no doubt the starters will also appear. At least that's what this teasing on Twitter suggests:
It seems that Tepig and Oshawott are also receiving their little announcement tweet soon. We will keep you informed as soon as the Gen 5 starters and Pokémon appear in the game!