Yes, the 18 Lohan are wai dan qigong. Any qigong that uses the limbs and movement to develop qi and the return it to the center is wai dan.
Da Mo wrote the detailed theory, actually a Buddhist sutra, of these movements during his "nine years facing the wall" at Shaolin. He wrote three others at that time too. (And, after he began teaching these things, the former head monk Batuo, who was the founder at Shaolin, finally accepted Da Mo into Shaolin, and became his disciple.)
It has been interpreted many ways, but its best to trace back to the root of Da Mo's Lohan and understand the theory of the movements as he intended them.
Jay Dunbar's looks pretty good. I am always looking for more versions of these exercises, keep them coming!
One thing I'd mention is, after hard-style qigong, your body can be overly-energized. Relaxing afterward may not be enough. You may also want to practice some soft-style qigong to get loose, or else you risk a stagnant feeling in the body. Stagnation is the root of many kind of illness, and it can make you feel tired, weak, frustrated, or depressed.