Rather than focus on the legend, I’d rather read it from a biblical perspective. A few things to consider; It doesn't say if Jack, the unsavory figure had repented as he would've gained entrance to Heaven if he had. The devil has NO say in who comes or goes to hell. If one has not repented that's where their going, end of story. :) God is the judge, not the devil.
A deceased Jack would NOT be walking the earth with or without a turnip as the Bible says in Luke 16:26 " And besides all this, between us and you a great chasm has been fixed, so that those who want to go from here to you cannot, nor can anyone cross over from there to us.’
The whole of the legend seems to me to speak of man's love of money which we know from 1 Timothy 6:10 "For the love of money is a root of all kinds of evil." After reading the article it seems it doesn't have much to do with a pumpkin at all. :) The enemy has his own set of tricks during this season, so let's set our eyes on Jesus and the truth rather than the tricks the enemy uses to keep our focus on legends. Pray effectively, use the word of God and have no fear of folklore. Amen!