I think points values change depending on the average. I was taking the northernmost countries quiz, missed one answer and still got only one point because the average was so high.
It aint pretty to look at but the DVD cover and movie poster actually list Eddie Murphy in a nod to the fact that he plays multiple parts often in the same scene: https://www.dvdsreleasedates.com/posters/800/N/Norbit-movie-poster.jpg
They were big in the early '70s doing stand up comedy and stoner movies - Up in Smoke and Born in East LA are the ones I remember seeing. Their "Dave's Not Here" sketch was a classic. I thought they were funny even though I was never high. Supposedly they were hilarious if you watched them while high. Cheech Marin is still around - I see him occasionally in guest shots on TV. The last movies I remember him in were Christmas with the Kranks - he played the older police officer, and Tin Cup. Tommy Chong is still acting, too, but I can't think of anything I've see him in. I remember his daughter, Rae Dawn Chong, played the female prisoner in that strange, prehistoric movie, Quest for Fire. She won awards for her performance even though there was no dialogue at all - just a lot of grunting and sniffing.
In the novel it's a bowler. In the film it looks like something between a bowler and a top hat. Wikipedia calls it a Sandringham hat, but I'm not sure if that's right.
Savant syndrome is now used instead of "idiot savant". It's a very rare disorder and about one percent of non-autistic people have it while some believe as many as a third or more of autistic people have some form of it - I personally don't believe the number is that high, but I'm not an expert I have a family member with autism. Savants usually have low IQs, while around half of autistics have average or high IQs. As Theodore indicated, the character in Rain Man was an autistic savant.
Rainman was Raymond Babbitt, played by Dustin Hoffman. His younger brother Charlie (Tom Cruise) called him Rainman because he couldn't say Raymond. But yes, the one with the disorder was in fact "Rainman" Babbitt.