Your math is uterly wrong. As it was stated a few times by others.
You have to move directly towards one model to hurt him with landslide. But nobody else will be in that aura since you can only deploy at least 7" away from any enemy model. So if you move on the line between Levy and the Waif 4", then you will be more than 3" away from both. Just place it on board and measure, you will see!
Anyway 1-2 cleverly placed models will deny you to place the Juju within 7" of either Levi or the Waif. So you won't get even one of them.
Sorry man, but your Levi destroying strategy is not working at all.