I HAVE NOT in fact BUT I WILL NOW. Gather round... I'll try to keep this short though I lost my ramble once alrdy...
8's dream was to teach others about her own culture + uniting octolings and inklings together in harmony, and Splatsville ended up being where that dream led her. She did live in Inkopolis for a while but grew disappointed with the indifference of inklings to anything but themselves, so with help from OtH she rented an apartment on the outskirts of Splatsville. She started working at a shelter near Hammerhead Bridge, where other Octolings much like herself trickled in after leaving the oppressive Octarian society. There she taught Inkling and Octoling languages, though she was still learning the Inkling language herself. 4 started volunteering in the same shelter in their spare time a couple months after. They didn't rly cross paths until 4 started bringin his guitar and playing music for staff and ppl staying at the shelter which caught 8s attention. The song that caught her attention was prolly Calamari Inkantation. They bonded over their shared love for music, at some point 4 invited her to one of his band's gigs (did I mention he's part of my splatband...) aand then they started dating after :3 They didn't know of each other's agent statuses at all till one thing lead to another, 8 introduced 4 to OtH and by extension reintroduced him to Cuttlefish & SS. Lots of angst w the latter but that's a wholeee nother story lol!