I've found Felix and his parents on the 1870 and 1875 census living in St. Wendel, Stearns County, MN. Parent John and Tonia/Antonia. Also Stearns County Historical Museum publishes an index to the all the Stearns County cemeteries up to (I forget which date) but it has John and Antonia and several of their children, as well as John's older brother Valentin and Johanna and several of their children. I've also found Valentin's emigration record, but not John's so far. Also see. www.mnhs.org
and then go to the Death Index for many of the Vouk's. On some of the census records, the name is spelled Wook, Volk, Wonk, Muck, etc. I found quite a bit by picking say Felix born in 1861-1862 and living in Stearns County, then just scan thru until you find his family.