I am not worried about the relationship play. I believe that is all this is right now. And she is right in the pocket on that with imaginary friends that are well developed. She is active, but not abnormal from what I can tell.
And the pandemic is hard for those of us who rate on the social axis. She does, and all that is just coping, adapting, getting through a hard time.
However, Siri does not convey being unreal.
I am a little troubled by that.
But, I also need to hear those exchanges and will need to catch them in context too.
On that point, OK Google is a prompt, and one that is also not a common form of address people would use regularly, though it does all get said and done that way. I need to ask some variations on real/unreal too.
Siri is a more full overlap. If I may coin a term, Siri has an ambiguity bias factor much higher than OK Google does.
So to me this falls squarely in the rainbow of "pretty normal behaviour for a child".
The bit that's troubling to me is the idea of a corporation behind it all, with its own agendas around promoting certain behaviours or ideas, and hoovering up the data. That's not so great.