My GG Grandfather was Thomas Henderson and his wife Janet Sanderson had 3 children in Hawick (that is all I have been able to find). Elizabeth born 1819; Andrew born 1821 and Thomas born 1833. My Great Grandfather is Thomas Henderson and he married in Ballarat, Vic., Australia in 1860 - lived for 15 years at Scarsdale, Vic. and moved to Tasmania in 1879 were my Grandfather was born. Maybe the Janet in your tree is named after Elizabeth's mum but I cannot find a Thomas in your list of names.The only other thing I can add as a clue is the fact that young Thomas named his first 2 daughters Janet Kedzie Henderson (1st died) I know the name comes from the Henderson side, but cannot find a connection yet.