Samhain? Sow-wein? Fluffies could pronounce that, but only if someone explains it; human English speakers have a hard time figuring out how to pronounce it, fluffies wouldn’t have a chance.
It makes sense, though, Halloween is like the worst night of the year for fluffies. Not only does everything turn creepy and weird, but you know edgy douchebags are sacrificing fluffies to Satan out in the woods.