Okay.... I'm currently rereading all of Jon's chapters. I just read the arrival of the NW to the Fist of the First Men and Ghost's discovery of the dragonglass weapons. I don't quite have a theory yet, just an inkling of one...
The idea is that Ghost is being warged... and not by Jon.
Jon notices that Ghost's colorings are the same as a weirwood heart tree.... white appearance with red eyes.
Ghost finds the hand and brings it while Jon and Sam are sworn in. Ghost is not afraid of the dead as are the dogs and horses.
Ghost warns Jon of Othor's attack. Ghost engages Othor, while Jon is terror stricken.
When they arrive at the Fist, Ghost will not enter although the horses and dogs will. Later, Ghost enters and leads Jon to the cache of recently buried dragonglass daggers and arrowheads. They are wrapped in a NW cloak.
Some of Ghost's actions can be explained by loyalty to Jon and courage. But some of his actions lead directly to the NW relearning lost knowledge... So how did Ghost know to find Othor and Jafer? Once he found them, how did he know the Old Bear needed to also see the bodies? Why was he bold enough to touch the bodies when all other animals shunned them? How did Ghost know to lead Jon to the dragonglass cache? Why didn't Ghost, upon discovering something weird, just mark it with his scent and move on?
If Ghost is at least twice controlled by someone to assist the NW, who could it be? Who has the ability to control Ghost, the access to Ghost, and the knowledge to benefit the NW? The first suspect is Benjen. Benjen is a Stark... that could explain ability. He met Ghost in Winterfell. And Benjen could have known what happened to his men and the value of the dragonglass and imparted all of that via Ghost, if.... he is Coldhands. Coldhands controls a giant elk and a flock of crows/ravens (I forget). Even if Benjen is not Coldhands, Coldhands could still be warging Ghost.
Another culprit is someone with whom Coldhands is friendly... the three eyed crow... Brynden Rivers, aka Boodraven. Brynden was rumored to be a sorcerer. He was a Targ ******* (do Targs have warging ability?) and once Hand of the King before being exiled to NW. He became LC, but disappeared north of the Wall. He is now literally dug into the world wide root and watches Westeros through the heart trees. If he can speak to Bran and Jojen through dreams and call to others through heart trees, it is not too much of a stretch to say he could slip into Ghost's skin. He is allied with the Children of the Forest, so he knows all about the dragonglass. I think it likely that he directed Coldhands to leave the weapons for Ghost.
I still need to finish ACOK, ASOS, and ADWD. I'm eager to read about Jon's experiences when Ghost is absent in ASOS and Jon's last chapter of ADWD.