Winnie the Pooh?
They all have heads?
Mack the Knife! 
Lou Gehrig
Ezzard Charles
Catfish Hunter
Kevin Tjrner
Professional athletes?
Leaffan: more specifically, thinkn about the end of their lives.
Oh. I guess they all died of ALS too.
Banjo, Bloodsucker, and Bartok
“Those are my attorneys.”
Yup. Turner is alive but has the disease.
I’m going out on a limb here: names start with B?
All are known for their smiles. (only because nobody said it outright yet)
You hit it on the… head.
None of these people have been in my kitchen.
Oh, right! An easy one, then:
Batman
Superman
Simeon Stylites
Alexis Stewart
Yes- their last names are all baby animals.
Yes!
Songwriter George M. Cohan
British Prime Minister Benjamin Disraeli
Writer Truman Capote
General George Patton
Writer Michael Crichton
Monty Python co-founder Graham Chapman
Scott “Santini” Powell of Sha Na Na
Roger Bannister, first man to run a 4 minute mile
All trained as medical doctors.
Yup- Bannister and Powell actually practiced medicine (Powell is an orthopedic surgeon and Bannister is a retired neurologist)