Dancing on a tightrope

Five years old, the books tell me, is an age when my daughter is not going to be that interested in her life history and experience tells me that’s true. But it is also the age when children start noticing the world around me, hence the various conversations I have had in recent months around the theme of “my child was asking why your daughter doesn’t have a daddy. What should I tell them?”
I know I should have the answer to this ready and waiting but I just don’t seem to get the right words. Firstly, which daddy? Her birth daddy, who as far as I know’s only contribution was biological, or the non existent adopted daddy which I choose not to give her? But even if I can give them the language to explain adoption to their child, is it my place or theirs to do this. I want my daughter to start controlling her story, but 5yrs is such a tricky age. I have shared with her what I know, in terms that she broadly understands, but this doesn’t mean she is ready to answer all the random questions a 5yr old kid can come up with, or to filter what she wants to share and with whom. Plus, 5yrs is also the age of imagination and she is filling the gaps in her understanding with fantasies – one time her father is dead and another time he is looking after another family because “if he isn’t looking after me he must be looking after someone else”. I want to correct her fantasies but I don’t have an alternative story to offer that will make much sense to her, never mind her school friends.
As if that wasn’t enough, her imagination is being supplemented by fiction. I had never realised before how much children’s films deal with issues around abandonment, search for parents, orphanages and adoption in one form or another. I had already mentally reserved any exposure to ‘Oliver’ and ‘Annie’ until she was much older but it is impossible to avoid – from Hercules to Kung Fu Panda to Despicable Me to practically every superhero it is constantly catching me unawares. In some ways it can be helpful to show her ‘good adoption stories’ but so many of these stories aren’t. I don’t know how much my daughter draws comparisons to her own history or whether it goes over her head. So do I raise the parallels and open up things she isn’t ready for (those same books tell me she would start thinking about her ‘alternative family’ much later in her childhood) or say nothing and follow her lead?
As always, I feel that building my daughters understanding of her life history is like dancing on a tightrope, two steps forward, one step back, trying to keep it all in balance.