My point is that throughout the presented history of Israel there has been an under-emphasised conflict between the Tribes of Rachel and the Tribes of Leah. Notice in your list the noticeable absence of representatives from the Tribes of Reuben and Simeon - the two eldest children of Jacob. Throughout the narratives of the Old Testament it is nearly always a younger child who is the chosen one to succeed (Seth, Shem, Heber, Abraham, Isaac, Jacob, etc...). Levi and Judah (the two younger of Leah's first birth period - and there is some theory that she only had these four sons; the other two, and the handmaid births, being later inventions to assimilate non-Hebrew tribes into the clan) were chosen by Jacob's god (the Elohim) to be the spiritual and temporal leaders of Israel. But Rachel's sons were the truly youngest, and possessed Rachel's gods (the Teraphim). Plus Benjamin's birth could be seen as extra special (through the circumstances I have already noted) in uniting together the gods of Rachel with the gods of Jacob.
As to the the 'teraphim', they were handed down to the tribes of Rachel, probably the Tribe of Benjamin. In the Book of Judges a new teraphim was created within the Tribe of Ephraim (Rachel), but this was taken away by the Tribe of Dan (Rachel's handmaid), who kept it until the Captivity. Rachel's original teraphim might have been handed down through the Tribe of Benjamin to King Saul, who passed it to his daughter when she married David from the Tribe of Judah (and note that she was the youngest daughter of Saul, whilst David was the youngest son of Jesse). The teraphim were used to help David escape from Saul's assassins. As I suggested, it was possibly a human skull, which explains the ruse used by David's wife.
The grail is not the Ark. The Ark is Elohim. The Grail is Teraphim. Elohim is male (Jacob, Moses, David, Jesus). Teraphim is female (Rachel, Micah's mother, Michal the wife of David, Mary Magdalene).