Dressing up as demons or devils, witches, sorcerers, might indeed be taken as an invitation for demon possession involving the transformation of the person's personality. Also, a Christian is expected to find such things repulsive as their heavenly Father does.
So going along with that custom is incompatible with Christianity.
Here is some backround info on Halloween:
THE TRUTH ABOUT HALLOWEEN
Is the Devil Jealous?
Well, he doesn't want to die but is scheduled to and can't do anything about it. Does he feel glad that others will continue living as after he is obliterated? No, he doesn't. Does he know that others who join him will share his fate? Yes he does.
Does he still try to convince then to join him? The Bible tells us that he will continue to do so even after the thousand year reign of Christi's over. So obviously he wants others to share his disaster.
Does this mean that he is jealous of the way Christians are in a relationship with God? No because he considers Christian obedience to God foolish. Only jealousy is in reference to others being alive after he is dead.
BTW
When considering angels one has to keep in mind that they were created above mankind in power and in intellectual abilities.
However, in order to maintain that status retention of holiness or respectful allegiance to our Heavenly Father was required.
Once rebellion set in holiness was lost and with it the intellectual abilities to behave rationally because creatures created in Gods image cannot go contrary to his will or behave disrespectfully without becoming foolish.
There is also evidence that some of these rebels have gone insane. That can be deduced from their insane behavior when they possess some people.
Screaming, growling, and rolling on the floor isn't what one might call sanity and if the human involved isn't responsible then the entity in control is and so deserves the classification of insane.