Maya Rigging & Blendshapes Problems
 

Hi Guys:
im now starting to rig one of my character for my thesis, since this is my 1st time to do this process, i have found some problems that need to be fixed as soon as i can.
1: I want to know that is it possible to remove the old spline IK and create the new spline IK for my character after it was bound without detaching my skin. In this case, i did my blendshapes for my entire character but not just for his face, after i create blendshapes, my spline IK with clusters dont work anymore, i guess it maybe because i should have done my blendshapes only for my face, but not for my entire character, the associated clusters on my characters spline messed up totally.
2. i have created a body skeleton with facial skeleton for my character, and i have bound them to my character. Now, i want to do blend shapes for my face only.So, can i just select the face and extract it from my character, and do blendshapes, then combine it again with my character and merge the vertices afterward to create a single mesh?
I hope you guys can give me some suggestions on those questions, and i really appreciate!