That small info about Rose being advised by some "Michael" fellow seemed a bit suspicious...
Yeah, the presentation presented "him" not so much as a person, but as a force. And since Michael means "Who is like God?", my personal suspicion is that this is the Black God itself. This is the way the fungal root was named in Japanese. Miranda was its prophet, its hand. Like Jesus for Jehovah or like the God Hand for the Idea of Evil from Berserk:
And Miranda indeed talks about it as if is's sentient.
Let's say that the "fruit body" of the mold has grown to the point where, like the Queen Leech, its intellectual threshold has increased. And so it can interact with people's minds in a representation, but in such a way that people understand it. These are usually visualizations, letters, names, whatever.
After all, it's a reminder that even the Pursuer didn't have human intelligence or even the intelligence of a Tyrant. It was a pure Nemesis parasite, but it could talk and use weapons like a human.
And from what we could gather Rose wants to live a normal life, what could that imply?
Rose is unlikely to be able to rewrite her body, so maybe it's about the power she stole from Miranda to help her father? This could cause unintentional chimerism or something else that would frighten children and other people. Like, when she grew up, she learned to control her body, but this caused problems in socialization.
This part is actually based on real science, oddly enough. The real mycelium is able to form structures that resemble those nervous ones that humans have, so they serve as a kind of biological Internet in forests that can "remember" and "store" information.
Once there was an experiment with a maze and sugar. Mold was released there, which grew its hyphae in all possible ways to reach sugar. After the fungus reached it, the experiment was repeated, but only with the extracted part of that mycelium. And it immediately found a shortcut to sugar.
And "our" mold, in addition to abnormal evolution (I believe due to the Progenitor Virus), is evolutionarily related to the human species, which is also not so far from science.
I think everything we see, as well as what we saw when Ethan communicated with Jack and Eveline, are kind of dreams. Representations. Only collective ones. The concept of a "brain in a jar" that explored The Evil Within as well. It's also something we saw in Little Miss and Raid mode in Revelations 2, only Alex used Spencer's digital technology, not natural.