I believe I found the 1910 Census record for Paul Junghans' eldest son, William.
It appears William was living in Sumner, Jefferson County, Wisconsin. Sumner is approximately 15 minutes southwest of Fort Atkinson, where the rest of the Junghans family would eventually be moving in 1914.
According to the census record, William was living and working on a farm.
I've not been able to locate a census record for William's younger brother Carl, so I do not know where he was living during the 1910 census.
This completes the 1910 US census records for the Junghans (Wisconsin) and Yunghans (Indiana and Ohio) families.