I can suggest two things to you, if you have not done them already.....
1. Search the appropriate US census films for where they settled.
Tracking them from the 1920 census backwards (much better than searching
from a certain date forwards) is the best thing to do, start with either
the 1920 or the last one in which they were alive. You can check the
section on US census on my Helpful Hints page. Searching the censuses
will give you information on children, year of naturalization and
possible year of arrival, and with that information you can go in all
kinds of directions....
2. If that area of Bohemia is now in the Czech Republic, those records
are not microfilmed. For those records you must send a request into the
appropriate archive, which can take a long time, but if you have a date
to start with they can find information for you. See the information on http://cgsi.org/archives/archive.htm
Your other query on relatives from Germany will also need to be
researched through the censuses.
The background on my research: Wenzeslaus and Barbara (WILD) MAGES emigrated
from Oberhutten, Bohemia to Redfield, South Dakota then to New Ulm, Minnesota
and later settled in Redwood County in Minnesota. His birthdate is 8-28-1833
and hers 2-16-1835. They had nine or ten children. Would like to know their
Marriage date, when and how they came to America. Only just found out the
daughters married names. The names are: Anna Reitter, Barbara Lampler,
Theresa Hogan, Laura Neudecker, Mary Lauden, Sophia Haas and Katherine
Gewerth. The sons were George (my husband's grandfather) and Wenzel. Would
like birth dates, marriage dates, names and dates of children.