You are right, in the beginning it was a callback to the day Urokodaki captured the demon 47 years ago. An interesting thing to note is, that the look of most of the demons resembles something that's important to them. Like the one in this episodes with all the hands, cause he always wanted to hold the hand of his older brother, when he was afraid.
Your comment to Nezuko "just sleep it off, instead of eating people" made me laugh so hard, it's so true!
Great reaction like always and see you for the next episode! =)