A while back someone mentioned “Ayn Rand Paul Ryan” as a portmanteau of various famous libertarians, where the surname of each preceding person becomes the first name of the next person.
If we relax the restriction that they have to be libertarians, we can add in Dinosaur Comics author Ryan North and Kanye/Kardashian baby North West to make “Ayn Rand Paul Ryan North West”.
If we throw that one away entirely and just try to make as long a chain as possible, I can do “Elton John Henry James Scott Alexander Hamilton” (I could go longer if I let myself use “Alexander Pope” and then “Pope Benedict”, but that seems like cheating).
Can anybody do longer? I think the rule should be the names have to be somebody you’ve heard of, not somebody you found on Wikipedia just because they had a convenient name.
Riffing on yours: Octavius Augustus John Henry James Scott Alexander George Michael Jackson