Mystery Monday: Zaza and Louis Waldman from Hungary to the Bronx

In my box of "unknowns" are three photos of siblings whose names I know, but not where they fit in my family tree.

At left is the undated photo, taken in the Bronx, which includes identification: The young lady is Zaza Waldman and the boy is her brother, Louis Waldman. Fortunately, there are two other photos.

At right is a photo of the siblings, apparently taken a year or two after the photo with names on it.

And at left, I have Zaza's graduation photo (8th grade?), also taken in a Bronx photo studio. All these photos had to have been taken before 1930. How do I know?

Because by 1930, I found the family living in Brooklyn. Zaza was 19 and Louis was 18 at that time. Zaza and Louis's parents were Julia and Joseph Waldman. And according to the census, all were born in Hungary.

Were the Waldmans friends of my maternal grandparents, Teddy Schwartz and Minnie Farkas Schwartz? Were they related by marriage to someone in the Farkas or Schwartz family?

UPDATE May, 2015: The Waldman family was related to my Farkas family, I discovered by finding Zaza's marriage info on FamilySearch.org. Her mother's maiden name was Julia Farkas!