Hello, Finnisfinder,
Can't be much helps as it appears all the people you are searching for moved out of the area.
There are no children recorded as baptised for Sara & Samuel Dixon or fro Christopher Selth & Mary Marsh.
I looked in Deal, Walmer and Shiolden records. All I found was the marriage of Mary Ann.
St Leonard's 14 July 1840 Christopher Thomas SELTH, Ironmonger of Beach Street, s/o Zachariah SELTH, Publican
to Mary Ann MARSH of Silver Street, d/o William MARSH, Mariner
Witnesses: William Bailey MARSH, Jane Lang MARSH, Mary Ann SELTH
Sorry can't be more help
Regards
AJ