Easter, Christmas and Halloween are all pagan in origin.
The bible never mentions celebrating Jesus birth at all, it doesn't even give us a date. Yet his death we were instructed to commemorate and a date,was given. That being said much of easter today is pagan in origin, not christian nor anything to do with Jesus and the meaning of the occasion.
Halloween is not mentioned no but due to its origins and non biblical customs / beliefs, I would never celebrate it.