Are you all arriving at the same time?
Anyhow, as a First passenger you are entitled to one guest each into the Concorde Room so assuming Mrs TWCLAM is also in F that's 2 guests into there.
If you and Mrs TWCLAM are arriving first and some time well before your Niece +1, go through the TFW which entails a BP check then security which will then take you into the FLounge which you then walk out of and into the CCR.
If your friends are arriving well after you and you are already in the CCR you can either meet them at the 'Magic Door' or via the normal entrance on the first floor. You can't go back out via TFW.
Enjoy your first 1st!