While people are eager to ship these old friends together, I'd like to explore an alternative approach.
That for her new life, Ran really doesn't want anything to do with her old Beastrealm life at all. Or maybe we can go further than that. Like, perhaps even before becoming Yukari's shikigami, she already outright despised the other beasts, and eventually managed to leave the place. Only until much, much later that she encountered Yukari.
Wait a minute... isn't the Beastrealm for the dead? Like, Saki, Yachie, and Yūma – they're dead, right? They're animal spirits. Meaning Ran in the past was an animal spirit... but now she's a kitsune? Does that mean when she left Beastrealm, she managed to restore her physical body and come back to life? Or is it actually the animal spirit itself that became a shikigami and possessed a nine-tailed fox?