I, too, am trying to locate a Sebastian born in Kentucky who migrated to Greenfield/Center Twp., Hancock Co., IN...I am trying to find David Sebastian.
David Sebastian married Malinda Hendricks on 26 May 1854 in Hancock Co., IN.We can't find him in the 1860 census, however.
I'm not sure if the following is the same David Sebastian but he is the only one I can find that "fits";
12 September 1850 Sebastian, David 35 Farmer 250 KY Sebastian, Mary 30 KY Sebastian, John L. 11 KY Sebastian, Benjamin 9 KY Sebastian, Cynthia A. 6 KY (1850 U.S. Federal Census, Center Twp., Hancock Co., IN, Page 174b, Dwelling No. 150, Family No. 153)
If it is, it means that Mary died sometime between 1850 and 1854 and David married a second time to Malinda Hendricks.
There is another Malinda Hendricks who married Armstead Ward in Jasper Co., IL.Malinda's family also settled in Hancock Co., IN, prior to migrating to Jasper Co., IL.Living with this family in the 1870 census is Angelina Sebastian, age 14.