I’m not too sure about the process then… if we have
One character A, a “default” one
One character B, as a resculpt of A (with the same mesh)
Is it possible to transfer the datas from B ot A, BUT in order to create morphs (shape keys).
The idea is to have sliders that allow to deform A to B.
To say it another way, imagine we have a default A, the idea is to be be able to use sliders to mutate it as a dwarf, a giant, an elf or an orc. Is there a way?
That is possible. There could be many solutions to handle the issue. Here are couple
Select A and B and use the shapekey pane to transfer it as a new shapekey. Repeat this for all the shapes.
Script it to transfer all the shapekeys.
Also someone recently released an add-on for a similar idea, maybe this is what you are looking for. You do not necessarily need this add-on to achieve what it offers, but it will make the process easier it seems.
Why not do the resculpt on a shapekey of mesh A - as long as the vertex count is not changed. Then you can simply add another shapekey for each new character. Or more wisely do multiple shape keys - especially on the face, so you can mix and match variations.
Also consider the classic game method for injuries / damage. Have another floating face that appears in place of the original. AKA swap out the entire face.
Another possibility - shrinkwrap A onto B (or C or D) as a shapekey.
Having said that - have you tried any of the modifiers - especially what is in the Modify column? I have never used some of them, and its been a long time since I have used any apart from Data Transfer so I cannot give advice. Read the manual, google.