I think Tsubasa might not be completely aware about HOPE. She might hear "whispers" but she isn't talked directly to, like Yasu. (maybe she is but unlikely)
It's safe to assume that the tree belongs to HOPE, in which case it would make sense if this tree had the powers required to pinpoint Akira at any moment.
I think that what happened is that Tsubasa realized at some point, that she can use this tree to connect mentally to Akira and began to speak through his mind, "narrating" the events that she sees through his eyes. She isn't the story's narrator, she just seems like one because she it talking through his mind.
This would explain why Touka suddenly appeared in his school and in his classroom, she found this interesting being, a broken man, who happened to be a teacher which she has been looking for a long time. That's how she found Akira and that's how she knows virtually everything about him.
Every god deity has a means to be able to pop into Akira's mind at any moment, it would make sense if the way they can achieve this is through objects, like the Tsukioka Tree, which opens another can of worms > maybe GODS deities aren't real, they are just humans pretending to be and using "TERMINALS" and "OBJECTS" to fake omnipotency. Akira doesn't believe in "GOD" after all, and Tsubasa is just a normal woman who can wield a form of telepathic omnipresence just with the help of an object
EDIT: Tsubasa could also be HOPE herself, or HOPE's wife, which is very far-fecthed but I have my reasons to believe this
If WIRES is Tsuneyo's daddy, then he too is a human, using these omnipotent objects to reach Akira telepathically and to remain barely alive