Debra,
I do not have additional information on Oskar. Due to the research of both my and my wife's family I only research and record family data for our direct grandparents and not other family members. Also, as the Voigtlander name is from the Leipzig area which was once under East German control, and my grandmother long gone, and my branch having moved North and East to the Hildesheim area in the late 1800s my data is thin. On the other hand it does sound like there is some connection between our past families. Best of luck on your research.
Regards
Glenn