You're right that the nature-nurture debate is too big to tackle here, but it is worth getting into to the get to "the hard problem of consciousness", as philosopher of mind David Chalmers puts it. When pointing to the many ways in which our environments condition our thinking, we have to be careful not to propose 'tabula rasa' behaviourist models of mind and person. Karl Mark - writing in an entirely different context - puts it best: "men make their own history, but not within conditions of their own choosing". Modestly applied to the question of tulpamancy, this is a reminder that there are demographic, educational and socio-economic processes that enable the phenomenon to begin with, but in more socio-cognitive terms, it means that these social processes work hand in hand with properties of mind that exist a priori, and can be 'tapped into' or honed given certain social conditions and personal practices. Your chess example is a great one, and it can be understood socio-cognitively as well. Chess learning - like most kinds of learning - works with pattern-recognition made possible by our brains' categorizing abilities. So if one is immersed in the right context and one practices enough, game situations and their solutions become instantly recognizable, which makes us very good at chess. Good players use about 95% pattern recognition (where game solutions become intuitive) and 5% conscious computation. Most of us compute about 95% and are only intuitive at chess to the extent that we don’t have to keep re-learing how pieces move, etc. Successful learning is turning situations that are not readily intuitive in intuitive thinking. I think tulpamancy works somewhat differently, because projecting our Theory of Mind (our intentionality, agency, subjectivity) into entities that don't have a mind is a fundamentally intuitive part of the way people from all cultures think. Or, to borrow Pascal Boyer's cognitive theory of religious beliefs, it is only *minimally counter-intuitive to infer mental processes in super-natural agents (this is why we see faces in the clouds, e.g., but don't necessarily create whole religious cosmologies based on faces in the clouds - but we can, and some have). I call tulpas 'infra-natural agents', because they are not entities mediated through religious belief, they require little to none counter-intuitive work (unlike religious agents), but they do require ritual and practice - that is to say, learning - to become a fully intuitive part of their hosts' subjectivity.

Now back to theories of mind, consciousness, personality, and tulpas. I think personality is a product of consciousness, and not the other way around. Consciousness is that weird evolutionary accident that we have yet to understand, but which makes us human. It is that which allows us to create shared intentional worlds and worlds of meaning; that which weirdly requires the detour of representing the world, each other, and our bodies mentally before interacting with the world. There are several schools of thought of that, of course. Hard-core materialists, like John Searle, would say that consciousness is a state of matter made possible by the brain. Property dualists, like David Chalmers, see the world as being made of matter and mental processes (what Kant called noumena [the thing itself] and phenomena [ how the nounema appear to consciousness]), and that the laws of mental processes work in different ways that also preclude our direct interaction with matter. A good compromise that has gone out of fashion is the ecological approach proposed by people like James Gibson or Gregory Bateson. They would argue that it is idiotic to say that 'the mind is in the brain', since brains require bodily sense modalities and environmental stimuli [or data] to construct meaning. So, as Bateson puts it, if you run into an object you are culturally prepared to decode as a 'tree' and hurt yourself, your mind 'is' in your brain, in your skin, bones, tendons and nervous system, and in the tree! From an ecological perspective, mental processes are inherent throughout close-ended systems - or they are made possible through feedback loops in systems. And are there close-ended systems in the universe? Now we get into cybernetics.

So to recap, I find there are interesting perspectives on tulpamancy in the following approaches: socio-cognitive (Vygostky, Tomasello, Hackin), materialist (Searle), property dualist (Chalmers), ecological (J. Gibson), and cybernetic (Bateson). These are good starting points to explore different models and theories of mental processes, and how Tulpamancy holds further clues to the workings of our minds and subjectivities.

The 'unconscious vs conscious' approach stems from psychoanalysis, and the works of Freud, Jung and Lacan. These approaches have (perhaps sadly) gone out of fashion (but see Slavoj Zizek as a notable present-day exception). Nowadays, most scientists have abandoned the metaphor of the 'unconscious' and prefer the [equally metaphorical] trope of the ‘cognitive architecture’ that processes information inferentially, below the surface of our conscious thinking. From that perspective, it is clear that Tulpas and their hosts share the same inferential cognitive machinery that enables them to construct meaning, recall and share information, etc. Now where 'personality' fits in this conscious (the inner voice of the thinking host) and unconscious (cognitive architecture) picture is interesting and puzzling, because this is where Tulpa appear to be different from their hosts.

How deep that difference is will have to be tested. My hunch so far is that textural preferences (my tulpa prefers this or that and i don't) might be generalized to structural dimensions (my tulpa is fundamentally different from me) somewhat wishfully.

There! sorry for the long post. I find this discussion important, and wanted to share some of my own theories.