Cult of the Dead connected to Kaddish?

“cultic customs associated with the dead, including some idea of resurrection, continued from Ugarit through the rabbinic period; these motifs seem to hibernate from our perspective, because the religious texts from the Bible and early rabbinic sources rarely mention them and certainly give them no sanction.”
– Mark S. Smith, “Mythology and Myth-making in Ugaritic and Israelite Literatures.” Pages 295-341 in George J. Brooke, Adrian H. W. Curtis and John F. Healey, eds. Ugarit and the Bible: Proceedings of the International Symposium on Ugarit and the Bible; Manchester, September 1992. Ugaritisch-Biblische Literatur (UBL), 11. Münster: Ugarit-Verlag, 1994: 303.

There seems to be an obvious historical connection between Jewish cult of the dead (broadly understood), celebrated by the first-born son for his deceased parents, and mourning Kaddish, also celebrated by the first-born son (preferably) for his deceased parents. It has apparently been ‘Yahwehized’ in the process, operating as a sanctification of the name of Yahweh rather than the name and posterity of the deceased parents. The very name suggests some connection with the cult of the dead (קדש).

And then there’s this:

“Absolve your nation Israel which you redeemed (Deut 1.28). The Rabbis expounded in the Pesikta, “…this refers to the dead who can receive atonement through the charity of the living.” From this we learn that the dead derive benefit from charity which the living sanctify in their behalf… This also applies to one who recites Kaddish or any blessing publicly in the synagogue, as… in the story of R’ Akiva (R’ Bachya, Deut 21.6).

I don’t know much about the origins of Kaddish, though. Has anybody written on this connection? Does anyone have a comment or suggestion? If there is a link or continuity between Kaddish and the earlier cult of the dead, it could shed light on both.