Are these items able to be vended? I haven't seen any so far and something in the news kinda made me think they weren't "grab yourself some uncursed cash and head down to the Holiday Shop to get your hands on these new haunted threads"

I don't think the news post means it's not vendable and I highly doubt that they're not vendable, but I haven't vended one myself to verify this.

I just vended this

i pulled one from the mystery box.

I haven't vended any of the pieces yet, either. Sometimes it just takes a while.