So I decided to reset my run, to gain karma and paragon points for the first time as I heard this increases production. However I am currently back to being able to produce alloy and I noticed I still cannot select a leader. Is this a bug or do I need to research something that I missed? for the sake of better answer I will also include my research and workshop upgrades that are available
From your screenshot, you actually are able to design a Leader.
In the list of kittens, locate the one you want. At the right-hand side is a white star. (Above the "Unassign Job" mention). Click on the star. It turns black : your kitten is now a Leader. He / she is now featured above the kittens list.
To change Leaders, just click on the star next to the future leader's name.