A short explanation of how the cycle works.
Almost anything can be a "PH" for the rare roaming spawns in this zone including Quillmane, Brother Qwinn, Sentry Alechin, Grizzleknot, etc... PH can be almost anything that wanders around... Lions, aviaks, elephants, wolf cubs, centaurs, etc.
The PH's will repop at a slightly longer time than the non PH mobs. PH's are ~78 seconds and non ph's are about 36 seconds. Anything that repops 36 seconds after you kill something is not a PH.
There are strategies you can use to spawn the rares quicker but it's much harder with others in the zone and without a tracker. With ideal conditions you want to kill a bunch of stuff simultaneously, time the repops and look for anything that took longer to spawn. Eventually you will get one of the rare wanderers to spawn. Could be Qwinn or any other named. Leave the named up as that NPC will only repop on the same PH.
Eventually doing this you can have all the rares up at once.
One hint which I'm not sure if it works on the TLP, but I did use it on live was there is always a wanderer PH that eventually paths over the same spot. That is right below splitpaw. If you wait there and kill it, eventually you will get a named to spawn. And then a new one takes its place and paths through that same spot.
Check this image to see what I mean. The blue area is a hill that you will see the PH come across and go right up towards splitpaw, or come the opposite way and go down toward the hill.