Your "1-9 list" seems more like an origin story for drama than for humor. However, a good joke is also a 'little drama'.
BTW, saber tooth tigers were extinct by 10,000 years ago. How did they go extinct? We wiped them out -- along with other megafauna. How did we manage to do that? Sharp objects.
Meanwhile, back at the comedy club...
I suspect laughter has more ancient roots than the lithic or neolithic periods, but you are spot on in identifying tension and relief as key elements. Our primate ancestors may have developed the vocalized relief breathing that developed into laughter. We also LEARN when to laugh and when to not laugh. For instance, if you see someone slip and fall in a muddy puddle, you probably won't laugh, being a sophisticated urbanite who understanding that laughing at other people's misfortunes is not just schadenfreude, it makes you look like a rube. God forbid! So, if you dislike the person in the muddy puddle, you'll laugh inwardly.
When we hear a joke that promises to be racist and/or sexist (what's black and white and rolls around in the sand), there is first a tension then a release, anticipating the punch line confirming our racist/sexist attitudes. These days sophisticated urbanites are never racist and/or sexist, so no laughter.
Maybe 25 years ago, The Prairie Home Companion Joke show featured a batch of "Your mother is so fat..." jokes. "Yo mama's so fat, when she fell down I didn't laugh, but the sidewalk cracked up." for example. The humor in the joke derives from the surprise exaggeration.
A major component of humor is founded on our negative beliefs and attitudes. Fat people (yo fat mama, for instance) are often the subject of negative attitudes which Fat Liberation (there is such a thing) tries to combat. I am too fat, and I have no time for fat people's liberation. [If you look at crowd photos from the 1950s, 60s, and 70s--all kinds of people--you will see far fewer fat people.]
So, are fat people legitimate targets of humor?
Satire and travesty are two kinds of more extended humor. Tom Lehrer (Harvard Mathematician turned satirist in the 1960s) said, 'When Kissinger won the Nobel peace prize, satire died." The next step after satire is travesty. Travesty too becomes impossible, at times--the entire Trump administration, for instance,