I know your message is from about 10 years ago, but wondered if you ever got your answer? I am doing research on this branch of the VanSickle family (trying to tie my own family in, as I'm 90% sure of relation). I have been in contact with the Northville Historic Society, and they provided me with information on the Henry Van Sickle I believe you are looking for, along with information on his parents. The information does show a marriage to Letitia Phillips, but also shows a birthdate for Henry of abt 1817. It notes that he was born in Seneca County, New York (probably near Ovid, NY), and that he married Letitia in Oakland County in 1853, and that he passed away in Milford in 1898. Please contact me if you would like more information, or if you have (in the preceding year) come across any information on this family. I am trying to connect my paternal great-great-grandfather Andrew Van Sickle in to this family (he would possibly have been a brother of the Henry you referenced).