Liam did not witness her birth, as he was out getting a heroin fix. Charlie saw her in the hospital soon after her birth in England. Megan was named after her grandmother.
The responsibility of caring for Megan was the reason Liam changed his life of music and drug abuse after pursuing her and Karen in Australia.
Megan should have been the one who inherited Liam and Charlie's Dexter Stratton ring. Liam gave Charlie the Dexter Stratton ring because he assumed Charlie would be the one to have kids. Charlie left the ring for Aaron Littleton in his crib but he never received it because Sun, who had possession of it, died.