Morphs are basically the flexes which are used in Source 1 to pose various things like cheek bones and so on. Importing your old flexes/morphs is relatively simple.
After importing your .qc into Blender, simply bring up your head along with the .vta and select both and export it as a DMX like below:
Importing the morphs into ModelDoc is the same as importing any other mesh, just import the .dmx as a new mesh and your morphs will appear on the bottom right under morph explorer. If you want to play around with them, simply enable manual slider control.