Control Point Modeling

You have to select at least the last two rows of control points of the surfaces edges to maintain tangency. Check out Rhino's "Select Points" toolbar. If you think it might be helpful, I'll make some additional macros or VBscript for selecting corresponding points.
 

Quad Meshes

This modeling technique allows to create meshes with quads only. You may use ApplyMesh to make unique meshes from more complex surfaces. This might be essential if you want to export to other applications.
 

Organic Modeling

This cartoon head was created in about 2 hours. For the mouth area the basic shape has been subdivided.