MIB
Sonnenfeld says he originally solicited suggestions from his crew, which resulted in 600 names. He whittled the list to nine, each chosen for a distinct reason. ”After we showed the film to Sony they said, ‘There’s no one internationally famous,”’ says Sonnenfeld. Which is why Sylvester Stallone was added. Fashion designer Isaac Mizrahi, on the other hand, was just a whim. ”He always looked like a Blue Meanie from Yellow Submarine,” the director says.
The chore was to procure permission from each celebrity (except for Newt Gingrich, whose image came from footage in the public domain). Though most were willing to go along with the joke (”He said, ‘I’m going to use you as an alien,”’ recalls Mizrahi. ”And I said, ‘All right. I don’t know what that means, but go ahead”’), not everyone got it. In fact, Sonnenfeld is still lamenting The One That Got Away: Michael Jackson, who refused to lend his image to the scene. ”Of course,” cracks the director, ”the real aliens say no.”
Celebrity aliens in ''Men in Black''
MIB2
Michael Jackson was approached to be in the original Men in Black film but refused. After seeing it in theatres and learning that a second film was in production, he volunteered to be in the sequel via his agent.
I very much wanted Michael Jackson to be in the first Men In Black.
There was a scene in it when we showed all these aliens and George
Lucas, Sylvester Stallone, Danny De Vito and Steven Spielberg were all
there and I really wanted Michael to be in it. But for some reason he
didn't want to be considered as an alien in Men In Black I. But 15
months into shooting Men In Black II I got a message saying Michael
Jackson really wanted to be in it. I had a lovely conversation with
Michael in which he told me he had seen the first Men In Black in
Paris and had stayed when all the other people left the theatre and
sat there and wept. I had to explain to him that it was a comedy.
Jackson said he would love to be in Men In Black II wearing the black
suit, all that mattered to him was that he wore that black suit. It
was very funny and it was entirely Michael's idea.
BBC News: Jackson wanted Men In Black role
MIB3
The celebrities were selected from a list of those who'd be willing to sign over their image likeness and big enough to still be recognisable in a few years time.
You know we don’t like to use that weapon too often. The hard part is
really figuring out the combination of who won’t be “who’s that
person” in 10 years. But so far we’ve been pretty luck and people have
been kind and interested.
I am surprised that Lady Gaga said yes […]
The challenge is getting celebrities that are famous, will give you
permission and won’t be like, “Who’s that guy?” in ten years. So
that’s one thing, the alien surveillance board that we’ve had in all
three movies.
Director Barry Sonnenfeld Talks MEN IN BLACK 3, His Oscar Caliber Performance in the Film, Filming in NYC, and More
It can be assumed that the politicians were simply selected for the rule of funny.