Christians only please? Dia de los muertos school inment?

My high school freshman daughter came home telling me of an ignment she had for Spanish cl, for Day of the Dead "Dia de los Muertos" (worth a test grade.) Students must either make Day-of-the-Dead Bread, or prepare an "ofrenda" for a deceased relative, complete with photograph, personal mementos, etc. The letter from the teacher described it as a "memorial display", but I see it more as an "offering" to the spirits of the dead. I used to teach public school. I'm NOT one of those religious fanatic moms that gripes about every little thing. This is a very conservative country school in Bible-belt South. I pick my battles, and often leave some for other more vocal moms to fight for all of us. But for some reason I am particularly offended by this. How should I respond reasonably? I am considering calling a couple of other moms to get their reaction before I do anything, and/or taking the ignment to my pastor for his take on it. What do you think?