Hello,
I have a fully sculpted ZBrush tool here… I was curious if this was possible: I export the model at it’s lowest subdivision level, modify it in my favorite 3D modeling program, then export the updated .obj… Then go into ZBrush and load this obj into the morph target of my tool so I can then swap to this new shape but all of my original sculpted data at the higher subdivision levels are kept in-tact. Is that a thing ZBrush can do? Thanks! 
EDIT: When I say modify I mean move the points around… I know that adding or removing points would destroy the point order and this kind of trick would not work.