So, let's see...

1. There's a mod that removes lalafell from the game.
2. There's a mod that removes (swaps) the 2B leggings...
3. There's a mod that can freely change the race and outfits of other players as they're displayed to you.

Seems to me someone just needs to link these things together. I'd suggest this idea remain a mod, however. No need to get the dev team embroiled in controversy by implementing it, and every time they make a change, and then worry about it getting dropped if they feel it's not worth the time and return. Not to mention, as a fan project you could have things like a database of immersive outfits to apply to other players at random, which would likely be too much time investment/upkeep for an official dev project.