Walkthrough: Just east of Poni Wilds is the Ancient Poni Path, a small area that is also home to Hapu. After reaching her, she will inform you that there presently isn't a Kahuna on Poni Island, as her Grandfather, the previous Kahuna, recently passed. She will then suggest heading to the ruins just off the Breaker Coast, in hopes Tapu Fini will choose another Kahuna to aid you.
Wild Pokemon:
Initial Pokemon - Daytime (Levels 40-43): Pelipper(30%), Gumshoos(30%), Granbull(20%), Exeggutor(10%), Gastrodon(10%)
Initial Pokemon - Nighttime (Levels 40-43): Pelipper(30%), Raticate(30%), Granbull(20%), Exeggutor(10%), Gastrodon(10%)
Trainers:
Collector Raymond - Level 43 Turtonator, Level 43 Drampa
Zygarde Cells: There are three Zygarde Cells and one Zygarde Core found scattered the Ancient Poni Path.
Items:
Adrenaline Orb - South of Hapu's House
Shiny Stone - North of Hapu's House
TM79 Frost Breath - Accesses By Entering From Poni Breaker Coast
Awakening - From Meowth In Hapu's House After Lying In Bed
Revival Herb - In Tree behind Hapu's House (Hidden)
Alakazamite - From Dexio (Post Game)
Key Stone - From Dexio (Post Game)
Poisionium Z - From Plumeria After Returning to Poni Island