Hi Mark!
I did my best to distinguish between selfhood and self-awareness in the essay, or being a self vs knowing that you are a self, but I was covering a lot of ground and I might have not been clear on my position. To answer your questions just from my perspective first, any living thing that embodies a dynamical system "thermostatted" to a fluctuating environment is a self, to borrow the technical term from your work. I definitely do not have the impression that there is a merely incremental scale of "complexity" (however quantified) and there is simply some critical value of this parameter where meaning just pops into existence, I'm not sure if thats exactly what you mean by the incrementalist view but I want to be clear that I'm advancing nothing of the sort. So my assertion was that meaning, which for me is a synonym for intentional self-world relationships, emerges with organisms and the fact that you have, ultimately, a converging series embodied in a physical system repeatedly interacting with an environment. Both the embodiment and repetition are necessary, however, for learning or adaptation to occur (and I consider both of those to be recapitulations of the same dynamics at different scales).
Self-awareness is a separate concept in addition to selfhood that had to evolve on a stable foundation of many interacting non self-aware selves, and my proposal is that the demonstrable gain in computational complexity generated by self-awareness is the selective mechanism which caused self-aware machines, once they had evolved, to outlearn non self-aware machines. I think the seeds of self-awareness are present in other social mammals if not all animals, but in the past few thousand years we became REALLY aware of our awareness, and aware of our awareness of our awareness ad infinitum and the same with the awareness of other humans. I don't know what the mechanism was that actually caused this change, but I presume it has something to do with social and cultural evolution, given that it's clearly too recent to be anything biologically or genetically special about humans, plus the fact that there appears to be nothing biologically or genetically special about us.
I hope that clarifies my views, and if nothing else I promise you I'm not defending a naive "just take the standard model and start adding complexity and poof!" view of the evolution of intention.
I can't comment on Dennet or Searle because I never studied analytic philosophy in any detail.
Finally, thanks for taking the time to read and comment on my work!