I've decided to work on an answer to
this thread and I want to check the plausibility of my scenario.
I've decided to follow Zoidberg12's
'The American Bonapartes' TL up until the Buonapartes leave for America. I branch off by having Letizia buy passage on a Spanish merchant ship in 1784.
While en route many of the people on the ship sicken from influenza and die, including all of the Buonapartes except for Napoleon. The ship's captain then exploits Napoleon by holding him as a debt peon, and forcing him to work off his family's passage.
Eventually the captain sells Napoleon to merchants working along the Mississippi river in Spanish Louisiana. The merchants use him as an aid in there trade with native tribes. Eventually a trade goes poorly when some Osage feel cheated by the merchants, who the Osage then kill, and take Napoleon as a captive to be traded to other tribes. Traveling west, the Osage encounter a band of Kiowa who purchase Napoleon as a slave of their own.
Thus begins young Napoleons journey to rise from a slave to a chief of the Kiowa, and unit the Comanche and other western tribes under his leadership. In his old age he would still introduce himself by his family name Buonaparte, but he would be more famously known by an English to Spanish bastardization of that name, El Rompehuesos, the bone breaker.