This was the most interesting part of the short for me. Especially 'Taken by figures in dark robes, male and female,' . It absolutely screamed Cowl and Kumori. Cowl has already set himself up to be a true nemesis to Harry, so why not give him a 'Dark Mouse' to boot.
That certainly seems like the implication.
While the narrative structure of nobody else understanding what Mouse is picking up because he can't communicate complex ideas to Hary or Maggie is cute for short story purposes, it kind of falls apart when we remember that Molly CAN understand him just fine. Dark, probably N-fected foo dogs working for probably Cowl and Kumori is something really freaking important to pass along, and ignoring that a suitable translator is around every week for family dinners at the Carpenter house would be a bit of a wtf? issue going forward if Harry stays unaware of it.
Or, hell, even Lea next time they cross paths - she'd be well motivated to continue checking names off her revenge list, if there's a lead on who gave her the athame.