Mary Ann Westcott was my g. g. grandmother by her first marriage (to William Cheese), so I have no direct link to Thaddeus, but I have some info on Mary.
She was born in Chagford, Devon, (31 March 1809), married to William Cheese (29 Mar 1829) and gave him five children. In the 1841 census she had put my g. grandfather (Richard Henry Cheese) into the Hackney Infant Orphan Asylum, but kept the others at home! She is described as 'Mangler' in that census and is a widow. I can't find much about the death of her first husband, William, apart from being in 1839, and she is living on Jane Street, a few doors away from Thaddeus. She is a widow again in the 1851 census, after the death of Thaddeus, and her son Richard Henry is living at home again and described as 'Biscuit Baker'. In 1861 he is a baker, and by 1881 a Master Baker. Were these skills he was given in the orphanage?
Mary is described as 'Monthly Nurse' in1861. She seems to use either of her married surnames.
Charles Krempoweicki was a witness on the marriage certificate of my g.grandparents, Richard Henry Cheese and Isabella Laing (21 July 1861) in Bermondsey, London.
I hope this helps a bit.