Welcome to the forums, psychomodo. I'm not entirely sure what you mean in your question though. I'll try to answer an important question that would precede yours, which is "Is there anything in the traditions this game is based on called 'Grim Fandango'?" The answer is no, but the title does bear significance to the actions of the dead in their afterlife, in my opinion.
If you didn't know, the game is based to some extent on Mayan folklore. So to make clearer what I meant earlier is that there is nothing in Mayan or modern Mexican folklore or history directly called a "Grim Fandango".
Although I'm not entirely sure where the title comes from, the only mention of a grim fandango is during one of Olivia's poems that she performs at the Blue Casket (The trendy club in Year 2). Here's the entire thing:Grim Fandango
With bony hands I hold my partner
On soulless feet we cross the floor
The music stops as if to answer
An empty knocking at the door
It seems his skin was sweet as mango
When last I held him to my breast
But now we dance this grim fandango
And will four years before we restI don't think that this poem is that significant to the Mayan theme in the game, but "Grim Fandango" is a good way to sum up the process that the dead must undertake. From the game, it can be seen that the traditions extracted from the Mayan culture showed death to be much like the stages of life, with all the natural rhythms. If life is like a dance, then death must also be a type of dance, however grim.
As for some links about mayan tradition and culture...I'm looking for some, I'll edit the post when I find some decent ones.
EDIT: You were right on about the calaveras though: For those who don't know what he was referring to, check these (
http://www.mexconnect.com/mex_/travel/jking/dd/fph152jkmuertos1.html) out. Also, here's (
http://web.raex.com/~obsidian/Mayapan.html) a breakdown of the Mayan pantheon, and some information (
http://www.pantheon.org/areas/mythology/americas/mayan/) on Mayan folklore and mythology.