According to the convict indent she was born in County Down and in 1833 she was a widow.
The Dissenters Baptism 1826 says that her husbands name was Michael LYNCHY (no "E") and her name is given as Sarah MULLEN.
On the daughter Mary Ann's death certificate in Sydney 1901 it states her father's name was James LYNCH and her mother Sarah MULLINS.
The home Office only allowed boys up to 8 years and girls to 12 years to accompany convict mothers and one son was left behind (possible Andrew).
Certainly Mary Ann was one child who came and her mother went to live with Mary Ann and her husband when she was given her Ticket of Leave (an early form of parole).
Cheers
Peter
Melbourne