With regards to use of photos, first are the legal rights of the photographer ... then there are personal rights ... and possible a bunch of other rights. I’m not a lawyer but do know that “model releases” exist for a reason.
So first step for making morphs for any character would be to get some decent photos.
I did find this warning with one of the images on Wiki for Sir Patrick Stewart
Personality rights warning
Although this work is freely licensed or in the public domain, the person(s) shown may have rights that legally restrict certain re-uses unless those depicted consent to such uses. In these cases, a model release or other evidence of consent could protect you from infringement claims. Though not obliged to do so, the uploader may be able to help you to obtain such evidence. See our general disclaimer for more information.
AFAIK, under no circumstances is one to use anybody’s photo for skin textures without having first obtained all the legal clearances required [check with local lawyers for details].
The basic idea is to load a squared image to the side and back grids in Hexagon, and then carefully morph the face to match. Start with a “grey” G or G2M which has been sent to Hexagon via the bridge from D/S4.x
Save the project file as this is likely going to take awhile.
Make the morph without changing the number of anything [dots, lines or faces]
Periodically save the project file, use incre saves.
Eventually when the face morph is ready for testing, export out the .obj to the desktop or some place easy to find.
Open D/S, using the bridge - send over to Hexagon the same base figure. Keep D/S open.
In Hexagon, import in the recent export [i.e. the morphed figure] ... delete the one that D/S sent over.
Selecting the morphed one in Hexagon, send it over the Bridge to D/S and make the morph.
If it’s a keeper [or usable anyway], “0” the morph and “save it”.