Tauros: "From Hala after defeating him in the Melemele Island grand trial."
Stoutland: "Speak to Mallow at Paniola Ranch."
Lapras: "From Lana at Brooklet Hill to investigate the splashing."
Charizard: "From Kiawe at Wela Volcano Park after completing his trial."
Mudsdale: "From Hapu upon entering Route 12."
Sharpedo: "From Grimsley on Route 15 after battling Team Skull in front of the Aether House."
Machamp: "From Hapu's grandmother upon entering Ancient Poni Path."
Mantine: "Visit the Melemele Alola Photo Club."
Solgaleo/Lunala: (do we have to put USUM spoiler warnings anymore?) During the climax just before reaching the Ultra Megalopolis.