Thanks everyone.
As promised let me first put down all the names and the related I recall from the Ramayan.
Ram, Lakshman, Bharath, Shathrughan, Dashrath, Kaushalya, Sumitra, Kaikeyi, Aswapathi (Kaikeyi's father also known as Kekaya), Yudhajit.
Sita, Urmila, Mandvi, Shruthkirthi,
Janak (I read that the name Janak was sort of a family name and that he was actually called Seeradhwaj. He and his brother Kushadhwaj were the sons of Hrisvaroma. The first person to have founded this kingdom - the Vidheha kingdom - one of the 16 ancient kingdoms - is Nimi. He was the son of Ishvaahu and was probably the first of the Vidheha kings. His son Mithi was the one who founded the city of Mithila (capital of Vidheha) and hence it bears his name.
Sunaina, Kushadhwaj (Janak's brother).
Apologies for the too long reply. Will post the rest when I get time.