rampart, thanks for your interest!
The faces are all done using the built-in face mapping of iClone 5. The woman's head is actually available as freebie in my store (Carla G5 at http://city.reallusion.com/store/animagic).
The face mapping procedure hasn't changed much in iClone, and there is a video tutorial somewhere. But I'll tell you what I do.
To design a face, I start out with the highest resolution image I can find of a front view, even though the final resolution will often be lower. The two gentlemen are politicians, so there were plenty of photos, but being politicians, they usually smile. This is a problem. So I had to edit the image to close the mouth.
I then import the image into iClone's face mapping tool. It would be nice if RL would make the window a bit bigger, but there is the zoom option.
In the tool you first crop the photo: above the hair line, outside left and right ears, below the chin.
Next you fit the outline of the head to the photo. First select Male or Female as appropriate, and then resize and reshape the outline so that the eyes and the mouth fit as best as possible. The outline will usually extend above the hair line; this is OK (the hair is actually in the way, so you could try and create a bold head in your graphics program first).
In the next step you will reorient the head to get the best line-up with the photo. This will not be perfect yet, as the mouth may not be quite horizontal.
Next you do your detailed mapping of various parts of the face. First you can use the mirror option the get the main adjustments right, then you can work on details such as the eyes. Here zooming in is very useful. If you have a side view that shows the ear, you can use that to further refine the head. But it is no absolute neccesity.
You're done. iClone will ask you to save the head.
At this point there are various ways to further refine your head; for example by using the head shape tools or by clicking the Detail button which opens a window where you can do even further adjustments. I use that often the better close the mouth or to reshape the eyes.
I'll also go back to the original photo to see if the overal shape and proportions are reasonable. Especially note assymetries (also when mapping a face). Most faces, even pretty ones, are not completely symmetric.
The resolution of the face textures has improved in iClone 5, but for higher resolution textures an external program need to be used. I don't have that so I make do. In some cases, you can improve parts of the face texture in a graphics editor by making use of the original photo.
I hope this helps.