why wasnt duchess at the ईद्भोकेट, क्रोकेट party?

I don't know.

But in the script of the Tim बर्टन movie, the Duchess had no role at all so why would she be in it during the ईद्भोकेट, क्रोकेट party?

I believe there was no use to put the Duchess in the movie since she wasn't in the script.