Unlike halloween Dia de los muertos has not been bought out by candy and soft drink corporations. It actually does reflect a spiritual time when people honor and pray for their lost loved ones. It's a day to honor those who we have lost and remember all of the great things they did in this life hoping they are now with god.
I'm not sure how people would take it if we started passing out Anon fliers to the public about scientology.
I don't think scientology would be well received in a heavy catholic community in a day of remembrance. I highly doubt they would have the audacity to show up to a holy event and try to tarnish it with propaganda.