It makes perfect sense that it originates from Irish folklore. I don’t believe the story you found is correct, because of the fact that pumpkins are native to North America. Faces were carved into turnips until Irish immigrants came to America and started using pumpkins instead.
That being said, we can Christianize most things. I learned somewhere than Jack-o-laterns were the faces of trapped, possessed souls. When my roommates decided to carve pumpkins this year, we flipped that meaning and carved happy expressions to show that our little pumpkins were saved souls.
My German roommates know pumpkin-carving as a USA Halloween tradition. The only pumpkin I ever carved though, was during school in the 2nd grade. Personally, I don’t like celebrating Halloween after having read the history of it. I didn’t want the pumpkins, but my roommates did, so we just kind made the joke for me, that the pumpkins now represent saved souls. I got some delicious homemade, German pumpkin soup out of it!

Also, here is a good article worth checking out, from Christianity Today. http://www.christianitytoday.com/ct/2000/octoberweb-only/42.0.html

Cheers.”

Thanks, I’ll try and do that in the future to avoid any confusion.

Cheers.