At this point, the whole discussion about Ivanka is nothing but Lashon Hara because there is no purpose. She accepted the same restrictions on her behavior that other people who are part of the KJ/Ramaz/Haskell Lookstein/East Side world accept on themselves. Please leave her alone.
A far more relevant discussion is whether the State of Israel should decide to stop accepting the future conversions of anyone who converts in Chutz La’aretz regardless of which Beis din converted them. If you want the State of Israel to accept you, then you ought to be required to meet their standards of “accepting the yoke of Mitzvos”, and you should need to go to the Mikva there. It would create a minimum standard and a registry of who converted and when.
As far as Ivana’s mother goes, apparently she is alive and well and living in the Czech Republic. Here is a cut and paste:
“Ivana Trump was born Ivana Marie Zelnícková on February 20, 1949, in Gottwaldov (now Zlín), Czechoslovakia (now the Czech Republic), the daughter of Marie (née Francová–possibly of the town Francova Lhota) and Miloš Zelníček.”
If you really have nothing better to do, then please track down Marie Francova Zelnick (AKA Ivanka’s mother’s mother) and ask her if her mother was Jewish. She probably remembers her mother’s parents too. I always thought that Marie was the equivalent of Mary. There aren’t many Jewish girls named Mary, but she was born in the 1920’s, so perhaps her parents gave her that name on purpose to hide her Judaism.
The source of this rumor is stormfront dot org May 5, 2016. It is based on Zelnick being a Jewish name which IMHO does not even qualify it as a rumor because Zelnick is not a uniquely Jewish name.