With the new Beard and Hair editor (not sure of the name), you can add a beard and / or eyebrows over the ones headshot generates.
I did the purchase the Smart Hair and Eyebrow Builder Pack that recently came out; I wish there more styles already.
I apply the eyebrows:
I switch the eyebrows to PBR, I am not a fan of the new controls. Then what I usually do, is apply an eyebrow opacity of a 100% black image. This still changes the image because there are 2 textures, but the eyebrows are more trimmed.
For the beard or mustache, you can do the same thing. Just apply a mustache over the one generated from headshot photo:
I have been meaning to do a new hair video, if you are interested I can make one.
Creator of the free website:
PixelDatabase.Net
A Free Online Text Based Image Editor