Two observations. First, I'm guessing the Papee is a typo and it refers to Virginia Rappe (or Rapee depending on whose spelling is correct). I think this is the closest I've seen them connected (and by lips no less) in print. Second, is the timing such that "Private Winter" is the cause, or result, of filming the closing scenes of "Shoulder Arms" at the Arcadia Balloon School. Happy New Year to all (we can still hope).
Chaplin filmed the scenes at the Balloon School a few months before in August or Sept. 1918 so it's hard to say if someone from the school was at this event because of that. It was a Red Cross benefit so military people would have been there. It may have just been a coincidence.You might be right that Virginia Papee is supposed to be Virginia Rappe.