On Apr 21, 4:45*pm, wrote:

* As far as I know, Steinitz had only one child, a daughter, Flora,
born to him and his first wife Caroline in 1866. The daughter
predeceased Steinitz, dying of endocarditis in 1888, which greatly
grieved her father. Wife Caroline (née Golder) was of English birth,
and nine years younger than Steinitz. I don't know anything else about
her.
* I know even less about his second wife, just that she was born in
Switzerland. Landsberger's "The Steinitz Papers" has a few documents
that indicate she got some money from charitable friends of Steinitz
to help with his hospital costs. Perhaps some of this money was still
there when he died in August 1900.

Flora is indeed mentioned in the obituary, but so are his two children
with his second wife:

“About two months ago Mrs. Steinitz, in order to maintain her two
children, opened a small candy store at 505 West Twenty-Sixth Street,
just beyond Tenth Avenue.”

“Prior to his being sent to hospital for the insane, Steinitz lived
with his second wife and two young children at 1555 East One Hundred
and Third Street.”

So, I guess the current mystery is whether these children were hers
from a previous marriage (or from Steinitz) and what happened to them
after Steinitz passed away.