A fictional character, did you give your name to a new brand of food in the past 30 years? - Dilbert: Dilberito - Wikipedia
Did you do terrible things but remain handsome until you died? - Yes, Dorian Gray.
Did your creator cry when he wrote of your death? - I’ll rephrase.
DQ:
Best known for dramatic roles?
IQs:
Before 1980, did your creator cry when he wrote of your death?
Were you a monarch who wanted to get a spaceship for your planet?
Are you an Italian woman often spoofed on SNL?
Yes! I am indeed Margaret Dumont, best remembered as a foil for Groucho’s humor. And, yes, she did know what was going on.
Trivia notes: she was raised by her godfather, Joel Chandler Harris, author of the Uncle Remus stories; she was the widow of a millionaire, and did occasionally do dramatic parts, as well as comedic roles where she was a daffy airhead (think Billie Burke).
Before 1980, did your creator cry when he wrote of your death? - Little Dorrit, created by Charles Dickens (hey, another D!).
Were you a monarch who wanted to get a spaceship for your planet? - The title character in Niven and Pournelle’s King David’s Spaceship.
Are you an Italian woman often spoofed on SNL? - Donatella Versace.
Did a political rival, to put you down in a debate, use your real first name?
Did you date the same girl that Mick Jagger did?
Were you JFK’s plump press secretary?
IQ1: Did you brothers step in to take your place in your latest movie after your death?
IQ2: Are you a college football coach who got your nickname because you wrestled a bear when you were 13?
IQ3: Were you lead singer for The Jam and The Style Council?
Correct as to all three Pierres, but it was the future Bianca Jagger who dated Pierre Trudeau, IIRC.
IQs:
Were you First Speaker of the Second Foundation?
Are you the best-known person to have been born on Corfu?
Were you the trainer of heroes in ancient Greece?