KEMMET from Ireland
I am also very interested on the Kemmet(t), Kimmet(t), Kemmit(t), Kimmit(t) surnames.
My roots are in Co Sligo where the name was widespread in the 19th century.
I have quite a lot of individuals in this county but also in the neighbouring Co Roscommon.
I have a Michel Kemmet, born 22 Oct 1834 in Roman Catholic, Taunagh, Sligo, Ireland. His parents were Thomas Kemmet and Catherine Coggins (alos Coggan).
I also have James Kemmit, born 22 Aug 1833 in the same place (parents : James KEMMIT & Margaret MILMO).
Both could be the people you have listed.
Finally, I have been in contact with a gggrandson of Betsy & Martin Tansy. He told me Betsy was born in Sligo in 1830.