This seems a rather open and somewhat vague question.
Famous in what regard... he's famous in the sense the show is aired around the world but if you showed a photo of him to a thousand random people would they immediately know who he is... no one can really say.
Just for the fact the show is international, and for a simple yes or no answer, Yes he is.
Intelligence
plutonium
its a catch phrase of stewie griffin
She Is The Daughter Of Lois & Peter Griffin & Sister Of Chris & Stewie Griffin.
because he watches Family Guy way to much and he loves Stewie Griffin & hes British.
Vito Corleone
Stewie Griffin would be spelled as "Stewie Griffin" in French, as names are typically not translated.
Lois Griffin
No, Stewie Griffin only loves Brian.
That would be Stewie Griffin: The Untold Story
Bart Simpson as he has been around longer and is a household name.
yes.
Intelligence
stewie is the son of peter griffin on the caroon series Family Guy.
plutonium
No.
No.