Neuromancer is one of my favorite novels due to its evocative prose, and vivid descriptions. However, I feel like sometimes I can't quite figure out some details. One thing that has puzzled me is why did Wintermute, the AI, end up splitting itself into multiple entities in the form of the Vodoun religion's Loas?
The Loas appear in both Count Zero and Mona Lisa Overdrive, though there is more direct speculation about what they are in Overdrive.
I can't immediately find a place where this is explicitly spelled out, but my impression was that Wintermute didn't transform into Loas. Instead, it used the various Loas as a way to communicate with humans. Since Wintermute transcended human intelligence, it found that it was easier to present itself as a god-like being. The Vodoun practitioners had access to both modern technology and their traditional mysticism, so made an ideal conduit for Wintermute.
This is not made explicit and my interpretation is that a specific answer to this question is not actually "known" in a left-brain sense by any of the human characters, but speculated on in some detail by several of the back-story/historical cowboys in several passages in both the latter two books, particularly Jammer but also Finn in Count Zero.
Basically IMO it's a religious analogy, small-g gods as archetypes, used to further man's social-technological evolution, related (IMO quite strongly and persuasively) to similar ideas spelled out in Neil Gaiman "American Gods" and Neal Stephenson's "Snow Crash" and "Cryptonomicon".
So whatever it is that the AIs became after merging (I'd put it as an "almost big-G" god but perhaps local to humanity and the Earth), having multiple "selves" as do we all (humans being made in "his" image after all), manifested them as the various houdou loa's as being "a good fit" for whatever "he" wanted to get done in his dealings with humans.
Beauvoir at al were able to capitalize on their open-mindedness and familiarity with that set of analogies and gain wealth and power making deals with them.
Mona Lisa Overdrive suggests that upon attaining global sentience the merged AI became simultaneously aware of "another", and in the wake of that knowledge, fragmented. The fragments then sought form, choosing the shape of Loas for the reasons given above.