I have found a baptism for an Emma Johnson - parents John and Martha Johnson at St Michael's, Ashton under Lyne, Lancashire.
There were also 3 other children at the same church , same parents between 1818 and 1822, but no Elizabeth, so still no proof of Emma and (the witness being sisters). Also the occupation of John, the father, was a Stretcher not a Carter.
I still haven't found a death for John Johnson.
Loz57