A question about Halloween costumes?

Well, there are two different parents to Halloween, the Celts, and religion. They really are the same, but the time period is what differentiates between what I mean, originally, costumes were worn by the Celts on All Hallows Eve to scare off the spirits. They believed that the connection between the afterlife was weakened on All Hallows Eve, thus the spirits could come to our world. The church morphed this, they developed a holiday known as All Saints Day, in order to honor the saints without a day. All Hallows Eve was the night before this, and as with All Souls Day, and All Saints Day, it was celebrated by dressing up as saints, devils, and angels. So, no, I doubt it is offensive. I wouldn't, not really, iconography should hold little importance to my beliefs. Halloween is for fun, and, honestly, I'm sure that if humanity really tried, everything could be construed as offensive.