There are great doubts about the descendants of Albrecht, Prince of Teschen (1897-1955). He certainly had two daughters from his second marriage, and this is beyond dispute. His alleged son Rudolf (1951-1992) appears in many sources (including Hein Bruins), but not in Angelfire. There are two alleged families of Rudolf in the sources. One version says that he married Natalia Radziwiłł and had two sons. I managed to refute this hypothesis because such Natalia Radziwiłł never existed, and her alleged parents (Leon Radziwiłł and Christine zu Windisch-Grätz) died unmarried and childless. The second version says that he married in Laurel, on May 1, 1976, to Anna Pringle (born in 1954), daughter of Lowndes Pringle and Carolina Suarez and had two children: Maria Louisa von Habsburg (born in 1976, died in 1990) and Ladislaus von Habsburg (born in 1981). However, only two secondary sources speak of this. In addition, I think the death of the alleged Maria Louisa at the age of 14 would have been reported in the media. So it seems to me that this version is also a confabulation.
The question remains whether Rudolph existed, but he died childless, or is he a hoax in himself?