I don't know how helpful this will be. I found a Rosst family in a village near Miroslav -- Vaclavov. I have attached two snips. The first one is the index that says there is a Katharine on page 197. The second shows that page. Readers, it's the top entry. Does that say Rosst? And what about the rest of it?
The two urls are:http://actapublica.eu/matriky/brno/prohlizec/1890/?strana=15...http://actapublica.eu/matriky/brno/prohlizec/1874/?strana=3
I don't see anything for 1846 and 1849 in the index or in the book for Miroslav.