My thoughts:
1. Daniel Paille is an essential part of this team, his speed and forechecking have made our PK successful since 2010. His hands may be stone, but there's always a spot for him here (though I've always been a proponent of putting Paille with Bergeron since their chemistry has always been good. I think the rest of the board hates the idea though so I'll give it up).
2. Cunningham is a keeper. Campbell had a good run, but Cunningham makes him redundant IMO. Similar player, but much younger.
3. That leaves an extra wing. We have a speedy defensive-oriented winger and a gritty two-way center already, what completes the line? What made Merlot the best 4th line in the league from 2010-2013 was that they could control the puck. Thornton wasn't an excellent hockey player by any means, but he could cycle and his physicality won the puck in the corners to keep it cycling. Who on the roster can replace that? Not Griffith nor Khokhlachev, or Spooner. Matt Fraser fits the profile, but I just don't think he's an NHL player. He's AHL+. Same goes for Robins. Only a temporary solution at best. Knight deserves a look, IMO. Camara could be that guy but he's a year or two away from the leap.
I guess right now I'd have to say Paille-Cunningham-Fraser if we're not making any roster moves. I don't really like it all that much though.
Alternate solution: Paille to Marchand and Bergeron's right, Smith to Eriksson and Soderberg's right, Kelly-Cunningham-Griffith.