Sole survivor can do all jobs at once. Last 30 years and completes 40 researches alone.
On my third run I decide to just let everyone die, see what happens since I haven't had a total fail yet. I made the game, put it on scarce, and clicked off the tab
At a certain point I clicked back into the game tab and saw I had one remaining villager, I decided to make him only eat plentiful food and put him on the gathering job, but for some reason, he wouldn't do the job, it would say he was an available adult, but wouldn't work. So I just hit all the jobs to see if he would do any, and then I noticed something.
Insight had gone up.
Food was also climbing, and I didn't have the scavenger perk yet.
So I started doing what anyone would do, and played the game with this sole survivor.
Progressing through the game, I found out a few things
1)He could do all jobs at the same time.
2)He could heal himself from wounds and sickness.
3)He still needs to eat and drink(I think)
3)He doesn't require tools to work jobs.
4)Materials are still needed to craft items.
5)There is no difference if I put "1 person queued" or "100Dc people queued"
6)Having the sole survivor die from wounds/sickness, or getting lost still causes the game to end.
7)He still ages and will die of old age (as he did in mine)
8)This problem continued through reloading the game multiple times.
9)His name is Rar, in honor of his village
So in the end this one survivor complete 40 researches, and lasted 30 years after watching his tribe die of starvation around him.
I also have (hopefully) attached the game files from when I thought to save, to right after he died of old age, the files between those are at random points in the game, and may differ between each other as I had died from wounds, sickness, and wandering off before I decided to keep him from doing anything dangerous during the few times I had to reload.