Yeah, I wasn't even including Rojo as I think he's demonstrated that he's awful at LB in the Prem, though maybe he's another one that was jaded under LVG. Blind is the only one out of that group I rate at LB as I think his intelligence in making runs and deliver adds alot to our attacking play from that position, but I would rather keep him at CB unless it's an injury crisis facing us.
You're right though Darmian can play there and TFM did see some time there, so perhaps Mourinho wouldn't shy away from giving him an opportunity. We'll have a better idea once Europa games start.