It must have been 1926 when Katharina's niece visited her from America because Budapest records show that Katharina (Tauber) Zerkowitz died 28 November 1926.Here's what I have on this family:
PHILIP [Fulop] ZERKOWITZ, b. Trencin, Hungary [now Slovakia], 21 December 1855, s/o Bernard Zerkowitz (1820-1894) and his 2nd wife, Rosa (Hochmuth) Zerkowitz (1830-1887); d. in Budapest, March 1, 1918, age 62 yrs.Philip m. in Trencin, 20 February 1883, his 1st cousin, KATHARINA TAUBER, b. Trencin, 9 April 1854, d/o Leopold Tauber (1803-1887) and his wife, Anna /"Netti" (Zerkowitz) Tauber (b. 1818); d. in Budapest, 28 November 1926, age 72 yrs.
Their children: 1.FRIEDA Zerkowitz, b. Budapest, 7 March 1885; living in Budapest, January 1950.Unmarried.
2.[son], b./d. in Budapest, 1886.
3.ROZA Zerkowitz, b. Budapest, 7 February 1888; d. at Auschwitz-Birkenau, 1944.Unmarried.
4.Dr. LEOPOLD Zerkowitz, b. Budapest, 14 December 1889; said to have d. at Auschwitz, 1944.He and wife [name not known] had two known daughters:(a) Magdolna Zerkowitz [b.1917; d. Budapest, 4 August 1918]; and (b) a daughter who survived the war and was a ballet dancer.
5.ARANKA Zerkowitz, b. Budapest, 9 August 1891; said to have d. at Auschwitz.
6.JOZEFA Zerkowitz, b. Budapest, 25 November 1894; d. Budapest, 12 August 1959, age 65.Unmarried.
I think the only survivor of this family is/was the daughter of Dr. Leopold who became a ballet dancer.Unfortunately, I know neither her given name nor whether she might have married and taken on a new surname.