I realise your post is very old, but I'm also interested in the Twelvetrees family. Charles Henry Twelvetrees (contrary to popular belief, I'm sure there wasn't a Charles R Twelvetrees) was born on 29 July 1872 in NY. His father was Henry, born 1847 in London, a carpenter.

Charles Henry the artist had a sister called Flora Amelia (20 April 1874 - 19 Jul 1909). Charles's son Clark married Helen Jurgens, who was Helen Twelvetrees the 1930s movie star.

Please contact me if you are still interested.