Synagogues sometimes keep member information such as family lists & yahrzeits of deceased family that the member observes .
They also may have lists of how the person is called up to the Torah. This will tell you his & his father's proper Hebrew names.
I am aware of someone who made a nice discovery this way.
I myself regret that I only pursued this avenue after the synagogue moved & these lists may have been discarded.
I hope this tip proves helpful to some.
SHERESHEVSKY Belarus esp Bialystok & Svisloch
AIDELMAN Belarus (Orly ?)
MANN Galicia esp Ulashkivtsi, Chortkiv, and Kopyczyńce
MANN Vienna Austria
MILLER / MULLER Galicia