Regarding the unity, I was talking about the unity of the self, not of everything. I was saying that even if there's no individual supernatural soul, there could still be an emergent unity of the self which makes it useful to speak of individual bodies, brains, minds, and so on. This is what I argued in the article linked below.

https://medium.com/the-apeiron-blog/buddhism-and-the-venture-of-limited-selves-beb4a25bfc08?sk=6584f3a565e2ef14433f4ffbce04477b