Thank you everyone for your feedback! It's been interesting reading the comments. I posted this same call for advice on another board and the majority choice was different.
I think each might be good for a different purpose. I was trying to get an honest portrait of the young woman who happens to be a model, rather than the young woman modeling. For me, 1 and 3 get closest to what I was after, but I'm not sure if it shows in the pics or if that was simply my judgment while taking the pics. For 2 and 4 she reverted to model mode, something I believe we all do with different levels of intent and skill when our portraits are taken.
Portraiture is pretty new to me so I'm trying to learn. Thanks for helping me.