If I am understanding your question correctly, SHAPES will be able to manage the blendshape part as well as the hooking up part for you. If you want to create it in another file, export out your node data from SHAPES. That basically creates 3 files for you which basically recreates your setup for you in another scene, provided that you have all the things it needs to connect up the system.
Once you export out your node data, in one of your post scripts you can add in the following:
“mel.eval(‘source “path to mel file.mel”;’)”
You do not have to do it in a separate project file, it might save you some extra steps of importing and exporting things from scene to scene. Use the control component to create the controls and layout your facial UI and hookup using SHAPES tool (Look on the Brave Rabbit website for some of these workflows.)
I hope this helps and hope it makes sense, if not I will try explain better.
Happy rigging man!