If I understood you correctly, you would need a script which finds nearest HP vertex for each LP vertex and then moves LP vertices to corresponding positions for other HP variations. Assuming only proportions change between different HPs, otherwise indices might change.
Maybe it's possible with bpy. but i don't know if you can store custom data like that on vertices with python. It doesn't even need to work procedurally, it just needs to be one button for lock and another button for snap. each vertex on the lp would need to hold a unique identifier for their respective hp vertex so they…