I have been looking into Todd in Anacarthy Co Tipperary as well, not related but they are one of my childrens ancestor through their father. I am fairly sure that William Todd born circa 1843 who married Bridget Ryan of Foilaclug and had 13 children is a brother your Margaret Todd ca 1846, as well as Mary Todd born circa 1855 and Nathaniel Todd, there is a strong possibility that they are the children of Thomas Todd who is mentioned in the Tithe Applotments for the parish of Anacarthy circa 1831. I did also come across on the internet a deed which mentioned both Dwyers and Todds
The Estate of Francis BULKLEY & John King FORREST, Esquires, Trustees of the settlement of Vere Dawson HUNT, Esq. situate in the Barony of Kilnamanagh and County Tipperary
Tenant's Names Tenure Cappagh Village Thomas TODD, reps of Martin DWYER Lease from Vere Dawson HUNT to Martin DWYER, dated 1st May, 1802, for 3 lives, viz: Martin DWYER, Jeremiah DWYER & Judith DWYER, two of which are in being viz: Martin DWYER & Jeremiah DWYER.
hope this is of interest to you