In this Hal community a "skin" is the GUI or the graphical window with which one uses to talk with Hal.
A character is the image of a person, animal or entity that we talk to under Hal's brain files.
Some confuse and interchange the two calling a modified character's appearance a "skin" but at least, now you know.
To view / interact with other than the girl and the frog, one needs to purchase the character expansion pack. It comes with a lot of additional Haptek characters with lifelike appearance and can be modified to an individual's preference.
One can also use MS Agent characters if desired.