Also Heat Metal will cause them to drop metal weapons on a failed con save. I can't think of any other ways but there might be. Make sure to pickup the weapon when they drop it.
If you're against fireball, then you're probably against smokepowder. Keeping Lae'zel alive is difficult for me too, having a martial Tav down on the ground with her sometimes draws some fire, the best I can do is buff her, and give her a shield, while doing what you can to break up the attackers.
