The scenes filmed in the FBI's conference room were shot on a borrowed set used by another FOX series, Bones. The wood paneling and decorations are the same (particularly the little glass hexagon sitting on the back shelf).
Jason Beghe stars in Chicago P.D. a spin-off from Chicago Fire. Monica Raymund stars in Chicago Fire.
Brendan Hines (Eli Loker) and DB Woodside (Henry Strong) both had recurring roles in Suits (2011) and they are both introduced in the same episode.