I sympathize with your predicament greatly and bentch you that your daughter return to the derech very soon.
Without addressing the situation in detail, one point that I would like to make in the benefit of the neighbors that you refer to. Dressing “like the average American non-Jewish teenagers” means hardly dressing at all. As such, for the frum men it becomes impossible to interact with her, as they are halachicly forbidden from even looking at her in that state. And if they speak to her while avoiding looking at her, it may be possible that she will take offence, exacibrating the situation. As such it may be best that women be at the forefront in trying to be mekarev her.
This is just a thought, and without knowing all the details just take it as “food for thought.”