The non-lethal attack toggle is a very inconsistent feature that seems like a half-baked idea Larian stopped developing mid way through.
You can knock out vendors and steal their ENTIRE inventory at no cost to yourself, but only some vendors
You can knock out enemies which serves no purpose.
You can knock out Alfira at the grove and she'll be replaced by Quil during the first murder cutscene for Durge, essentially saving her from otherwise certain death (and keeping her quest reward later on)
But you can't knock out Minthara and encounter her again/recruit her at Moonrise, which is arguably the same mechanic as Alfria
Use non-lethal on Minthara would be the perfect tool for recruiting her to the party without all the nonsensical bullshit and wouldn't necessitate changing the pace of Act 1 or 2 very much, if at all. She's clearly a well thought out character that only suffers from rushed, cut content.
