With regards to Martar IceBear / Tundra Jack interactions, a post dated Mar 15 2000 at
http://eqbeastiary.allakhazam.com/search.shtml?id=658 shows that Tundra Jack would assist a player in killing Martar. Another post dated August 29 2001 confirms what is implied by most previous posts -- he's aggressive to at the very least Barbarians. This doesn't appear to be the case here; he cons kindly to my Erudite Enchanter, warmly in Barb illusion.
Karg IceBear on the other hand seems to be a friendly fellow. He has some quests available, and will fight Martar if they encounter one another (see post dated October 9 2000 at
http://eqbeastiary.allakhazam.com/search.shtml?id=3611) No clue as to how Karg interacts with Tundra Jack, though because Karg is a friendly NPC.