For Mollie, the most likely Yiddish/Hebrew name would be Malke/Malkah. Others might be Michle or Mamle. And then each of these might have various YIddish nicknames.

Have you tried just searching M* Schiff? More likely than not, your relative chose an English name that began with the same letter as her Yiddish/Hebrew name. 

I have a great great grandmother Michle, who in the US went by Mollie, Minnie, Mamie, and Minnie in various census records. 

Michele Lock
Alexandria, VA