Here’s an add-on for assigning one or more Bezier curves to another curve as its shape keys.
It also supports multi-spline curves, with a number of part matching criteria.
Download Location: https://github.com/Shriinivas/assignshapekey
Script Name: assignshapekey_2_8.py
This is an early release, so I would appreciate it, if you would report back defects or issues that you come across.