The Swanson surname is very rare, there are only 4 families recorded in the whole of the 1901 census. Therefore the one and only Swanson family in Co Wexford is almost certainly yours:
http://www.census.nationalarchives.ie/pages/1901/Wexford/Wexford_Urban_No__2/Furlongs_Lane/1807399/Bridget is 11, almost matching the year of birth you have for her.
There is one other Swanson in Wexford, Maggie aged 18 living with her Grandmother aged 80 in William Street. Maggie must be either an Auntie or, more likely, an older sister of Bridget. Either way it looks like you may have a family link back to the 1820’s.
By 1911 there is still only one family of Swanson’s in Co Wexford and they are still resident in Furlongs Lane, Wexford Town:
http://www.census.nationalarchives.ie/pages/1911/Wexford/Wexford_No__2_Urban/Furlong_s_Lane/696948/There are some inconsistencies between the two censuses. Whilst the age of the Head of the family has as expected gone from 40 to 50 the forename has changed from Michael to William. However it is not unusual in this part of the world for different forenames to be used. Eliza has gone from aged 4 to Lizzie aged 13 which is consistent.
As William had 10 children, 7 of whom are no longer living it’s highly likely John has died between the censuses.
William is stated to be married and not widowed so it’s possible his wife is still alive. She could be in an institution (hospital, workhouse etc) where initials rather than full names tended to be recorded. Or has she travelled somewhere with her daughter Bridget who as you say is not around?
(The following looks like the marriage of your GF Richard Callaghan’s older brother, William: date: 7 July 1908)
