I have determined that another sister of Emma Böckler and Dora Böckler was Katie or perhaps Kathe Fleitmann, born about 1860. They were friends of the Achelis, Vietor, Smidt, and Spies families. She had at least two children, named Clara, born in (NYC?) in about 1887, and Josephine Warthling Fleitmann, born in about 1878.
I have a photograph of the three sister visiting their mother, Emma Möller Böckler in Bremen in the 1880's. There are also many photos of Kate and her daughters.
I see that the name Fleitmann is somewhat common. any help?