@Glûk the Bard i appreciate the level of detail youve thought about this, but I guess I should clarify the actual backstory and what happens, based completely on IN GAME dialogue.
-Team Skull was originally formed by the unnamed Kahuna, prior to Nanu.
-The Original Skull was formed in retaliation of Alolan Traditions. The Kahuna abused his spot of power after being chosen by Bulu as the Kahuna. Tapu Bulu was not aware this would happen, and by the time the Kahuna had already begun forming Skull, it was too late.
-Eventually, Tapu Bulu retaliated, destroying and disbanding the Original Skull, The Thrifty Megamart (Which is now Acerola's Trial Site), and the Tapu Village as well. Despite the Tapu Village's initial good intentions, Tapu Bulu overlooked them in it's rage and destroyed most of the area.
-After the older Kahuna's death, Nanu was unwillingly appointed as the new Kahuna of Ula'Ula island.
-Guzma ran away from his home on Route 2 after failing to complete his Trials and become a Trial Captain.
-Though he was too young at the time to be a part of the Original Skull, he simply took inspiration and rejuvenated the team in his own name. He made himself leader and appointed Plumeria as an admin.
-Guzma's Skull has been operating for about a year now, and It is approx. 5 or so months until the story of SM/USUM Takes place. In two months, Lillie will flee Aether with Nebby, and then three months after that, the MC comes to Alola and begins the actual storyline.
-Nanu knows Looker from his older days as an Interpol Agent. Although I imagine Looker has not been to Alola in quite a while, Nanu has kept up with the man and knows of Anabel and Emma through Looker.
-Let me be clear when I say: Nanu does NOT have any darker intentions. His story is complicated, but he, in no way, is a bad person or has darker intentions. He likely has PTSD from his time as an Interpol, as well as a good chance of depression. He's just an old man stuck with the title of Kahuna.
-Nanu overlooks Po Town because he's fully aware of what Team Skull is capable of. He makes no move to "stop" them, since he knows 99% of the current Team Skull is just a bunch of kids with nowhere to go. Compared to other organizations such as Team Rocket, Team Skull is not a threat. However, he is more or less not aware of their cooperation with Lusamine and other Aether Paradise members.
-Likewise, not ALL of Team Skull is aware of the fact they're working with Aether. Only Guzma, Admins, and certain higher-up grunts are aware.
-Speaking of Team Rocket, the anime has also recently confirmed that Nanu and Giovanni know each other. Take that with a grain of salt.
-Once again, Team Skull is not a huge, mafia-like organization. It's run by a 23-Year Old man who likes bugs. 99% Of Skull is just misunderstood kids who view themselves as failures, there's no actual criminals. While it's entirely possible for characters in the RP to deal with themes of abuse, drugs, etc, it's completely unrealistic for Team Skull members to start suddenly whipping out guns and having a police standoff.
With that said, I hope EVERYONE takes the time to read some of the points here I've made. I want everyone to keep in mind only about 20% of this is headcanons, a HUGE chunk of this is all based on text from the actual games, both SM and USUM. While I enjoy the flexibility of an open RP, just please try not to go overboard and OOC, okay? If you have any other questions, PLEASE feel free to ask me and I'll do my best to clear things up.