Since you've chosen to bring the Bible into the discussion, you may want to recall that Proverbs speaks to the value of a multitude of counsellors. As to the "speaking in tongues" reference, that might be better handled in another forum.
I work with the public and I say Happy Holidays for a couple reasons. First, I have no desire to know their religious affiliations. Secondly, the phrase really encompasses the whole holiday season, rather than one specific day or celebration.
I think it's a bit like the old question : "How many angels can dance on the head of a pin?" If there is a finite answer and you discover it, will it really make any difference?