What if while Korra and Asami were in the spirit world, they accidentally ran into one of Korra’s past lives and that avatar was so happy to see her like “man Korra I’ve been looking EVERYWHERE for you! By the way, have you seen [lists all the avatars]” (Korra and Asami bored af) to which Korra responds “you mean, you’re all still here?????” “Yep, we’ve just lost connection with each other. Can you help reunite us?” And that becomes Korra and Asami’s mission in the spirit world cause only Korra can reunite them or something
Bonus: Korra and Asami meet a kind spirit who grants them a family or a spirit becomes their human child
Bonus 2: all the past avatars giving them [sex] tips and helping them through the difficult times of their relationship
Bonus 3: Aang is so fucking happy that there are more airbenders. The past air nomad avatars connect with the new airbenders to teach them about obscure parts of their culture.