A few things..
#1 is your best shot posted..The shadow is a bit dark for my taste in this pose..Maybe a reflector fill on her right side to soften the shadow a little, or you could dodge it in Post....As others has said..the fingers should be folded under loosely. But a great expression, none the less.
#2 Piano is distracting at that angle....The right hand is cut off..a quick fix is to have her hold her hand around her belly, just below her chest...The lighting is nice.
#3 She needs more light in here eyes...and her right hand needs to 100% in the photo by posing it differently....The Pose is nice though..
In portraits with both hands in them, it is important to have the whole hand in the photo..without cutting off the fingers...it a guide line...here is one that works with partial hand and leg...notice the tight crop too. the leg and hand are part of the borders too.
All in all...you have some good ideas here..just a little tweaking..that's why you posted them..for the tweaks advice from many photographers..