Houdini tells Stratton a story about himself at age 9 in which his mother called him Harry. Houdini had not adopted his stage name at that age so his mother would certainly have called him "Ehrich".
When discussing the "aliens", Houdini notes "We don't have to call them Martians, there are seven other planets in the universe¹." which would imply he had included Pluto. Houdini died in 1926 and Pluto was not discovered until 1930. Houdini should have only counted six other planets.
¹ Houdini incorrectly said "universe" instead of "solar system".