I tried many different BCDs before I made my decision and purchased my BP & W. Contrary to what you have been told, it doesn't matter what type of diving she is doing, she only needs a BP&W for any and all different types of diving environments. And, you can't try one on out of the water to get any idea of what it dives like or how comfortable it will be. And, no the webbing doesnt rub me.
I would suggest that you rent one and have her dive it. And, dive it a few times - not just one or two dives. It does take some adjusting to get it right. They are made to fit so she will have to adjust the straps but the beauty of it is that when she has her own and gets the adjustments made to fit her, she only straps it on and dives. No BS. I have custom weight pockets that fit on my waist strap when I need more weight but the beauty of it is depending on the water temps and the suit she wears she may not need weight at all. I dive a custom made short heavy steel BP and in fresh water with my 3 mil, and I dont need weight. When I dive in saltwater or with a heavier suit I can either add weight in my pockets or attach my heavy STA and I have no problem. With the STA I dont need extra weight. This is nice because my hips dont get bruise from wearing a weight belt.
I would suggest she get an entire Hogarthian setup so she doesnt have a dangling second stage. She can wear a backup around her neck with a bungee and it doesnt get in the way. Her pressure gauge will be a small gauge clipped off to her left hip and not a console that gets in the way or hung on something while diving. My depth gauge and compass is worn on my wrist and it all very simplistic. I would be happy to talk with her if she has questions. R