Yes, Jennie died in infancy. Erwin "Ernest" J Little survived until at least 1940. He died before his mother in 1953 as he is not mentioned in her obituary. Ernest went to Wausau and worked in the paper mills there. He and his wife Emma had a daughter named Karen. I have not found out what happened to her yet.
The next trip to Wausau I'll try to find out more about them.