Did she marry as Margaret Thomas?
There is a Catholic marriage in 1866
Margaret Rimmer - father James to Edward Thomas
Edwardus Charles Rimmer Thomas Birth 24 Oct 1866
Baptism 4 Nov 1866 St Anthony's, Liverpool, Lancashire
Father Edwardi Rimmer Thomas
Mother Marguerita RimmerTHOMAS, EDWARD CHARLES RIMMER mn RIMMER
GRO Reference: 1866 D Quarter in WEST DERBY AND TOXTETH PARK Volume 08B Page 413
Edward Thomas age 4 is with his Rimmer grandparents James & Roseanna in 1871 Piece 3812 Folio 130 Page number 31
Marriage 10 Oct 1844 St Mary Highfield Street, Liverpool, Lancashire
James Rimmer Father Henry Rimmer
Spouse Rosanna Crosbie father John
RIMMER, MARGARET mn CROSBY
GRO Reference: 1845 D Quarter in LIVERPOOL Volume 20 Page 407
Added
Margarita Remmer Age 13, Jacobi & Rosanna
Confirmation 24 Oct 1858 St Oswald, Liverpool, Lancashire
Liverpool, England, Catholic Confirmations, 1813-1926