Quoting you Bhagat ji,

"Again, there are sections of Dasam Granth that are unique to that scripture.
What are your views on when comparing nanakian philosophy and your common sense to Dasam Granth?"

So take a look at the first line you have cited above

Page 1368, Line 3
Speaking the word "Kaalkoot", then uttering the words "Kashtkari, Shivkanthi and Ahi" and then adding the word "Dhar", the names of Baan are known.133.

The historical background for this Dohra on the name of "Baan" in the Shastra Naam Mala, an inventory of weapons, was well known to the followers of Guru Gobind Singh, who probably heard this hymn recited many times. Probably the Shastra Naam Mala was meant primarily to be heard as a poem, rather than read, because it is written in Braj which was the literary language of poetry in Sri Guru Gobind Singh's time. His followers were aware of the Vedic mythology that is alluded to in the shastra.

When one takes the line apart, the first image is the image of Kaalkoot. Kalkoot is a reference to a mythical poison and figures in the concept of Neelkanth Mahadev, or by analogy, "savior of the world", in this way.

Shiva and Brahma ask Lord Vishnu to save the world. The story is long; so imagine a chaotic scene where demigods think they have smelled amruth (amrith). Once they figure out they are really smelling the aroma of Kaalkoot they all try to escape. A madhouse ensues. The aroma of Kaalkoot is very poisonous. So the Lord Vishnu, Shiva and Brahma have a dilemma on their hands. To save the world, Lord Shiva inhales all of the poisonous Kaalkoot. However he does not swallow it down but harbors it in his throat (in some accounts in his belly). Lord Vishnu and Lord Brahma are very thankful, and Vishnu bestows on Shiva the name Neelkanth (literally blue throat) because when he swallowed the poison his throad turned blue. Allegorically Neelkanth means he saved the world. Shiva explains that “poison” can never be completely eliminated because one must at times make sacrifices to help others (the moral of the tale).

In another story, the dilemma of amruth vs kaalkoot is better explained. Everyone in Hindu mythology knew that amruth is an intoxicating drink that lures the naïve and ignorant to think that they will become divine. This however did not always happen, and more often than not the aroma of amruth led the prideful seeker after immortality toward fatal attractions in Maya. The ones who drink Amruth, which is the nectar of immortality, can become devas, but they never reach beyond that classification. Those who drink kaalkoot become Mahaadev, the greatest of the divine because of the sacrifices they have made.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-sikhi-sikhism/41-teachings-guru-nanak-dev-ji-guru.html
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=41

The meaning of Kaalkoot should aide in our understanding and Guru Gobind Singh’s point should be pretty clear. But let’s continue.

I am not completely satisfied with my understanding of Kashtkari, Shivkanthi and Ahi and perhaps another forum member can help me out with this. But these words seem to signify people and regions of northern India where the forces of Gobind Singh were bedeviled as much by hill tribesmen as they were by Mughal forces. Kashthari may refer to forest people, and these words also hint at regions where significant battles were fought. As I said, I am very unclear on these points.

Dhar in the context of Dasam Granth represents righteous deeds, or to perform righteous deeds, deeds inspired by consciousness.

So some connections are emerging – One must make sacrifices and harbor if necessary a deadly substance (or a weapon perhaps), if one would take the action needed to save the innocent and the righteous. One has already made these righteous sacrifices in recent battles. One continues in sacrifice to the end, and we get to the end of the verse as well, to the word Baan.

The point of the Dohra is to know Baan completely. Baan is a deadly weapon and it is our protector. Baan is also the arrow of Rama, enlightenment. The arrow is poison to our enemy, but taking up arms in a righteous cause is dhar. Unless it is infused with consciousness, Baan is nothing. As our Guru's reframe this idea, they say,

Ang 332, by Sant Kabir

ਗੁਰ ਕੈ ਬਾਣਿ ਬਜਰ ਕਲ ਛੇਦੀ ਪ੍ਰਗਟਿਆ ਪਦੁ ਪਰਗਾਸਾ ॥
gur kai baan bajar kal shhaedhee pragattiaa padh paragaasaa ||
The Guru's arrow has pierced the hard core of this Dark Age of Kali Yuga, and the state of enlightenment has dawned.

When we assume the moral duty of making painful sacrifices (inhale the Kaalkoot) in the midst of all we have suffered, and we do the righteous thing, then we also come to know Baan, the arrow that pierces our heart. The word Baan is also Persian for “host” or “keeper” and also guardian or protector. When we assume the moral duty of making painful sacrifices (inhale the Kaalkoot) in the midst of all we have suffered, and we do the righteous thing, then we also come to know the power of Baan, the Protector.

The forces of Guru Gobind Singh knew the story of Shiva, the Neelkanth. It was part of their culture, past and heritage. I had to go looking for it. They also must have understood that the story contained within it a moral choice dhar and a moral lesson "sacrifice." The verse takes them however to several levels of understanding and it ends with Baan. A reminder that spiritual consciousness inspires the arrow and gives it power.

Similar idea is found in Sri Guru Granth Sahib Maharaj

Ang1396

Raag Sava-yay (praise of Guru Amar Das) by the bhat, SAL

ਧ੍ਰੰਮ ਧਨਖੁ ਕਰ ਗਹਿਓ ਭਗਤ ਸੀਲਹ ਸਰਿ ਲੜਿਅਉ ॥
dhhranm dhhanakh kar gehiou bhagath seeleh sar larriao ||
Holding the bow of Dharma in His Hands, He has shot the arrows of devotion and humility.

On panna 1357, of Sri Dasam Granth, an evern more dramatic connection appears. I will try to post it soon. Forum members, please correct my errors and forgive my ignorance.