Mustang now knows whether Wistrit is Lust, as he has investigated him. Grumman and Ed might also possess some valuable information. We only have two civilian roles left, and one of them is Kitz, so the probability of her being Lust is quite high. However, I was puzzled by how skillfully she concluded the investigation on Leanna – either it was just luck and a well-used opportunity to prove her innocence, or a clever tactical move (in my opinion, premature, as the investigation might not have been guessed correctly).
But overall, if you think about it, it doesn't matter to us who we hang – Kimble or Lust: the former used his overpowered ability, and the latter has no defenses left that she can break through. So, I'll be the first: execute Leanna.