So I recently offered to help a fellow student with his senior film rig and I've been facing issues with previous work which was done on the file.
The character had already been fully rigged before being handed to me, but lacked some features which the director requested that I include. In order to do so, I attempted to create a couple of local rigs - one with joints and the other with lattice deformers for squash and stretch - and everything went smoothly until I attempted to create blendShapes to put everything together.
What happened at this point was that the joints and skinning which had been set up by the previous rigger stopped working while the blendShapes were active. Upon some research, I came to find that this was an issue with the order of deformations, and that I could fix that by changing the order in the Inputs window. Whenever I attempt that, however, I get the following warning:
// Warning: line 0: skinCluster22 is not deforming face_geoShape. //
Not knowing what to do at this point, I decided to attempt to detach the skin from the original skeleton and found that the geometry was being deformed by the joints even though all the set up controls were set to 0/neutral. The character's head is looking slightly to the right, rather than being fully neutral. Which meant that when I tried to re-skin the geometry, Maya did not allow me to, giving me this error:
Skin on _joint was bound at a different pose. Go to the bindPose to attach new skins.
I have been unable to go to a bindPose, getting the following error:
// Error: file: C:/Program Files/Autodesk/Maya2014/scripts/others/gotoBindPose.mel line 84: No object matches name: //
And at this point, I have no idea of what to do. My only plan of action was to perhaps create my own skeleton for the head - but doing so would also imply re-creating a skeleton for other areas of influence, such as clavicles and so forth, which I would rather avoid unless if absolutely necessary.

If anyone can think of a solution for me, or figure out what the bindPose error means, I will be greatly thankful.