I haven't heard anything on this and wondered if anyone else has. I would love it if I could get a Dead Orbit hand cannon, scout and machine gun like the Venation III, Crypt Dweller and the Deviant Gravity.
Dead Orbit needs a sidearm too.
-
http://www.vg247.com/2016/06/15/destiny-rise-of-iron-check-out-sweet-new-armour-and-weapons/ One gun I see here looks to be from the Vanguard. Not sure about the rest of your question.