Like Paul teaches the Corinthians, the answer would depend on the context, who gave it to you, and their impression of it.
Pagans and Romanists "gave" this holiday to us as meat sacrificed unto idols. We all know that meat sacrificed to idols is perfectly fine to eat, as long as the eating of it is totally divorced from any religious significance. Paul's language makes me think of meat wrapped in ordinary, brown paper that you buy at a butcher.
What Paul calls sin is eating meat when someone tells you, "This is sacrificed unto idols." This isn't meat in brown paper, but it's meat that someone has wrapped in "sacred black paper" (even if only in the mind). The second eating the meat takes on a religious significance in the eyes of the world, we are actually communing with devils when we eat it.
What I'm saying is that Halloween is pre-wrapped in idolatrous significance. You can try to celebrate "Halloween-lite" in your home and around your neighbors, by avoiding the most blatant excesses of the holiday, but you're still having fellowship with darkness.
Maybe there will be a time when carving pumpkins at the end of October and going door to door for candy will be without any reference to Halloween. That time has not arrived.
I don't really, but even if I did, my inconsistency would not invalidate the argument I'm making. My impression is that during Christ's millennial reign, there will be plenty of occasional days of thanksgiving called by the church, but none of the holidays you have mentioned will be celebrated.
This objection seems to come out quite often when people are frustrated with others for wanting to remove monuments of idolatry. Here's what [edit: Samuel Rutherford] has to say about it.
“The names of dayes to signifie civill times and things, out of a religious state is necessary now: and the Holy Ghost doth use for civill signification such termes, as Mars-street to signifie civill and meerely historically such a place. And the Ship whose signe is Castor & Pollux, yet these were heathen names, and most superstitious, and cannot be used in a religious state. I grant, we may not term our Jehovah, Jupiter or Baal; nor Christ, Mercurius, though he be the word of Gods mind to us, for God teacheth us other words and language in his Word. The truth is, that a learned noble Lord said well and judiciously, ‘all the indifference (in the world) lyeth in our understandings, and the darkenesse thereof—but there is none in the things themselves, or actions, which are still either unlawfull or necessarie.’ And this is most true in actions morall and humane.”
The Divine Right of Church Government, “A Dispute Touching Scandal and Christian Liberty” p. 54.
If the Holy Spirit used pagan names in a way to merely designate objects or times, we should not trouble ourselves with it, too much. When I call the seventh day of the week, "Saturday", I am not "getting in the spirit" of Saturn, and no one thinks I am, either. The same cannot be said about a person actually engaging in Halloween festivities.
