This group was by no means limited to Leo Spitzer, Erich Auerbach, Walter Benjamin, René Wellek, Roman Jakobson, and Ernst Cassirer. Heaps of intellectuals got the heck out of Germany (and the rest of Europe) when Hitler was elected. This group had a pretty ever-changing roster of folks, but some people tried to attend every meeting just to make the newbies feel welcome.
People were so impressed that he wrote Mimesis from memory that there was no question he would be president.
Mikhail wasn't a German émigré—he was Russian—but just because Germany and Russia had become mortal enemies in World War II didn't mean he wasn't welcome in the group. He and the group bonded over their rejection of totalitarianism—whether it was Communism, Fascism, or Nazism. The group was crushed when this brilliant semiotician got deported to Kazakhstan, so they kept him as a member in spirit.
Leo made sure to record the life experiences of all members of Intellectuals in Exile. After all, it's the daily, personal detail that counts. Members had endured a lot of suffering and still produced amazing works of criticism, so Leo felt that—at the very least—they could be a lesson to us all.