Yeah, Pathik is an odd fellow; he's definitely not Earth Kingdom judging by his accent, but he doesn't fit any of the others as well. In nature, he seems to be more like the Air Nomads than anything judging by how he reacted to Appa's hostility.
I'm more curious about his ability though; it's pretty much the same thing Huu did in the swamp, but Huu showed Aang how to use the tree as an intermediary to find Appa and Momo while Pathik just directly used Appa's spirit to trace Aang. So it's basically the same skill, but Pathik is able to use it without a medium.
So is it just something that people with a strong connection to the Spirit World can do or is it a special ability that these two men share (though Pathik's version is much more advanced)?
I believe that they (or at least Pathik) trained themselves spiritually, immersing into the spirit realm and eventually gained these abilities. I love these kinda characters; Pathik may not necessarily be a Bender, but that doesn't mean he's useless.
Well, we can't be sure if they were also born with a strong connection to the Spirit World or trained to be close to them, or both =( In ancient Chinese stories, it's often that someone chooses to abandon secular life, meditate and receive enlightenment. Hermit things.
Oh, that reminds me! I want to know more about Iroh's ability to see spirits. Remember how he saw Roku's dragon? Did his son's death lead him to a pilgrimage? God, I love this series. So many possibilities.