What a great trip you will have. Looks like you have some good leads to finding family, and enough to keep you busy looking at records until you go.
I think I found your Mary (Maria Anna) Smazenka's birth record, born 20 Jul 1893. (Married in 1912?...would make sense since she didn't come to the US with the rest of the family.)
http://actapublica.eu/matriky/brno/prohlizec/5150/?strana=12...Yes, Maria Anna Smazenka married 6 Jun 1912 to Jan Veverka who was b. 24 Jan 1889
http://actapublica.eu/matriky/brno/prohlizec/9995/?strana=10...