It looks like you have been looking along time for your Joseph Sladek. Today is your lucky day. Joseph Sladek was born March 12, 1857 in Budejovicke Predmesti, a part of the city of Pisek. His father was Joseph Sladek who was the son of Jakob Sladek and Anna Krivanek. His mother was Rosalie, who was daughter of Jan (John) Vaneck and Katerina Masek.
Joseph had several siblings, viz Anna b. Kvetna 27, 1854, Maria, b. brezen 22, 1852, and likely others, but ran out of fun time.
Your Joseph married Barbara Kucera on 2-17-1894 in Michigan. in 1887 he married unknown, didn't have time to look it up. Likely the reason son Joseph is born in 1890.
You can dig for yourself at ceskearchivy.cz, parish of Pisek. Especially books 17 and 18. Catholic books.
I will attach the image of Joseph's birth record.
Jean I will be off line for the next week. Try posting again if you need additional help as there are alot of good searchers out there.
I am not related.