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Sun and Moon leak
Trevor now works as Professor Sycamore's assistant and he's researching Mega Evolution. There are 10 mega stones you can get by talking to Trevor, he will give you directions and instructions how to find them (the rest of mega stones you can find by yourself)
Tierno has a new dance school which is basically a place where you can teach Dance moves to Pokemon (like Swords Dance, Quiver Dance etc), he's a "dance" move tutor. You need BP to teach those moves to your Pokemon
Shauna opened up a new butique in Lumiose which sells clothes and accesories worn by past protagonists. It is the only place where you can buy them. They're very expensive