Well I got the icepaw bear with the icepaw paws, and that was a bit neat (not as noticible as I would like though) ~ i let him get killed and his paws vanished. I then did the tranq on the bear and tamed him that way to keep the icepaws... I'm just scared to let him die again
I'll get him killed later today, and then i'll see if the tranq did anything different to the longevity of the icepaws.
The easiest way to figure out what you're tryig to do, I think, would be to use the tranq on one, then kill it.
If the ice paws remain, then they would also remain after taming on a pet (when using the abandon macro for buff-taming). If they disappear after the wild mob dies, then I think there's no way to get permanent ones on the pet, sadly.