Late, but w/e.
As of December 29, 2016, I already beat the game, but I'll get down what happened anyway.
Lillie and I went to Exeggutor Island to get the Moon Flute, but it rained, so we took shelter in a nearby cave. Lillie told me about her mother's caring side, which was heartbreaking considering Lusamine's sanity slippage at Aether Paradise. After the rain cleared, we got the Moon Flute and made our way to Vast Poni Canyon's entrance. There, Hapu battled me to test my worthiness of going through the canyon as the island's grand trial. I wondered why the grand trial would be at the start of Poni instead of the very end, but I went through with it anyway. Because my team was well-equipped to deal with Ground Pokemon, this wasn't a hard battle.
Afterward, Lillie and I went through the canyon, with her healing my Pokemon several steps of the way. She went through her own personal trail of running across a bridge, even with 3 Murkrow attacking her. On my own, I met Poni's trial captain, Mina, who simply gave me a Fairium Z without a fight before pondering about her own art with me as the subject.
Towards the end of the canyon, I went through an abandoned trial site, where I battled the Totem Kommo-o. I could have beaten it down with Primarina right away, but I chose to let it live long enough to summon its Hakamo-o and Scizor reinforcements for the extra experience.
After climbing a really long staircase, we arrived at the Altar of the Moone, where we played the Sun and Moon flutes that made Nebby come out of the bag and evolve into Lunala, the very Legendary Pokemon we sought. It took us to an Ultra Wormhole, which led to Ultra Space.
Ultra Space was a weird place, but not as weird as the Distortion World and it was crawling with Nihilego, the Ultra Beast I fought earlier. There, we met Guzma, who recalled that he got possessed by a Nihilego before pointing out that Lusamine was beyond reasoning. Nevertheless, Lillie gave it a try anyway as Lusamine appeared on a rock. Lusamine was unfazed as she sent out a Nihilego she had caught and fused with it to horrifying levels, and challenged me to a battle. All of her earlier Pokemon were given totem boosts, but I was able to play around them. After Lusamine was beaten again, she tried to kill Lillie, not before Lillie was able to summon Nebby to our side and undo the fusion. Lusamine fell unconscious after reconciling with Lillie.
Dozens of Nihilego surrounded us and Nebby warped us out to the real world, where Hapu was on the altar. She took Lusamine and Guzma back with her. Nebby then expressed a desire to continue to travel with Lillie, but as she wasn't a trainer, she decided to let it travel with me instead, but I had to catch it. After only a day of resetting for good stats, I caught Lunala. Lillie decided to leave me behind after deciding to do what she can to cure her mother.
Afterward, Nanu showed up out of nowhere and offered to take me to the newly formed Pokemon League, which I accepted. After some grinding, I went to Mt. Lanakila and battled Gladion at the base and Hau before the League itself. After even more grinding, I met Kukui at the League building and explained the rules: I couldn't leave until I beat all of the Elite 4 or got beaten myself. Knowing that I could have done them at any order I wanted, I decided to battle the Elite 4 from left to right, from Hala to Kahili. I hadn't seen Kahili at all during the full adventure, though, while Acerola took the Elite 4 position after Nanu refused it.
After defeating the Elite 4, I went to the champion's room, where Kukui congratulated me for making it this far before challenging me to one final battle. The one Pokemon I had to play around the most was Decidueye, as Lycanroc had set up Stealth Rock and broke Lunala's Shadow Shield. I had to use Full Restores in hopes of stalling out Spirit Shackle, knowing that Decidueye would KO Lunala with Spirit Shackle without Lunala's Shadow Shield.
After being officially crowned Alola's first Champion, the professor and Elite 4 congratulated me and held a festival at Iki, where most of the main cast of the game celebrated (Lusamine couldn't make it and Mina was off somewhere). Lillie suggested we sneak off to the Ruins of Conflict to thank Tapu Koko, but I was more concerned about the festival. She was frustrated and dragged me there anyway. Lillie healed my team one final time before I interacted with Tapu Koko's totem. To my surprise, it battled me. Knowing that I couldn't save in between, I simply KOed Tapu Koko with Dugtrio's Earthquake so I could come back for it at a later point. We returned to the festival, where everyone was still celebrating. Lillie was about to tell me something, but decided to hold off at the last minute as fireworks were in the sky.
The day after the festival, Hau rushed into the house, reporting a disaster at Hau'oli Marina. It wasn't much of a disaster, but a disaster regardless, as Lillie was leaving for Kanto to start her own Pokemon journey and find a cure for Lusamine's condition, with Bill as her starting point; he had fused with a Pokemon himself. Hau was devestated at the departure; I was, too, until Lillie gave me her good luck charm, a Poke Doll. As Lillie's boat left, Hau was left sulking, but Kukui encouraged him to give one last smile to someone dear who left.
We went our separate ways after that, with Hau training himself to battle against Hala and me returning home and receiving a shady letter about coming to Route 8's motel. I also battled the Eevee users for Kagetora, who failed as he had to start a family before he could. Each of the Eevee users struggled with their own problems at their old age, but nevertheless continued to live on in their own ways. I also rebattled Guzma at Hau'oli Beachfront and Faba at Aether Paradise.
Current team:
Primarina, female, level 69
-Hydro Pump
-Scald
-Moonblast
-Psychic
Nature: Serious
Muk, male, level 66
-Knock Off
-Brick Break
-Gunk Shot
-Crunch
Nature: Hardy
Ability: Poison Touch
Dugtrio, female, level 66
-Iron Head
-Stone Edge
-Sucker Punch
-Earthquake
Nature: Hasty
Ability: Tangling Hair
Vikavolt, female, level 66
-Bug Buzz
-Thunderbolt
-Energy Ball
-Agility
Nature: Rash
Kommo-o, male, level 66
-Dragon Dance
-Sky Uppercut
-Dragon Claw
-Poison Jab
Nature: Adamant
Ability: Bulletproof
Lunala, level 66
-Moongeist Beam
-Calm Mind
-Focus Blast
-Psyshock
Nature: Timid