Sorry for such a long reply. I had started looking years ago and with no luck quit. Now, I've been fired up again.
Yes, I'm sure it's Droz because Victor and Stella were my grandparents on my father's side. Now, what it was before Victor's parents came over? Who knows. It could be any variation, Drozdowski being the most common Polish version.

Please, let me know if you've found any new information.