Dunno any of those, Prof. P.
M.
- created after 1900
- best known from a film or films
- might be alive today if real, but unknown
- first name starts with M
- created after 1975
- not from a science-fiction or fantasy genre film
- considered a “good” person, I suppose - certainly not an outright villain
- not from an Academy-Award winning movie
- created before 1999
- from a comedy
#1 was Benoit Mandelbrot.
#2 is Mary Wintergreen.
#3 was James Mason.
3 DQs reserved.
Not Moaning Myrtle, not Farmer Maggot, and dunno (Beetlejuice and Rumpelstiltskin spring to mind, but I know they’re not right).
M.
- created after 1900
- best known from a film or films
- might be alive today if real, but unknown
- first name starts with M
- created after 1975
- not from a science-fiction or fantasy genre film
- considered a “good” person, I suppose - certainly not an outright villain
- not from an Academy-Award winning movie
- created before 1999
- from a comedy
- Live-action film
- not an especially common first name
- created after 1990
Correct x2.
#3 is Superman foe, Mr. Mxyzptlk.
DQ: Protagonist?
SCAdian
110
IQ1: Is there something about you?
IQ2: Did you write Der Freischütz?
IQ3: Would you have been proud of the way I was moving when I passed that crowd?
Not Mary (with or without jism in her hair), not Manfred (?), and dunno.
SCAdian
113
Correct.
Carl Maria von Weber (another person whose middle name is always used).
Mario Andretti (“Uneasy Rider,” by Charlie Daniels).
I don’t even want to know what the jism comment means…
IQ1: Were you a dog flying in a biplane?
IQ2: Were you really J’onn J’onzz?
IQ3: Were you 86?
Not Morticia Addams, dunno, and not Mary LNU.
Time for you to see the movie again: http://akns-images.eonline.com/eol_images/Entire_Site/2014520/rs_1024x759-140620112429-rs_1024x759-131104124556-1024.theres-something-about-mary-hair-gel-diaz.jpg
Neither Snoopy nor Manfred von Richthofen, not the Martian Manhunter, and dunno.
Correct on Morticia.
#2 is Madeline Ashton.
#3 is Mae Mordabito.
2 DQs reserved.
SCAdian
116
Muttley (Dastardly and Muttley in Their Flying Machines).
Correct.
Maxwell Smart.
DQ1: Blonde?
DQ2: In more than one film?
I’d have to have seen it before I could see it again. 
Well, you should! Gross but funny.
M.
- created after 1900
- best known from a film or films
- might be alive today if real, but unknown
- first name starts with M
- created after 1975
- not from a science-fiction or fantasy genre film
- considered a “good” person, I suppose - certainly not an outright villain
- not from an Academy-Award winning movie
- created before 1999
- from a comedy
- Live-action film
- not an especially common first name
- created after 1990
- not the protagonist
- not blonde
- not in more than one film
IQ: Were you played by Sally Field in Mrs. Doubtfire?
That was Miranda Hillard.
3 DQs reserved.