I’m not sure I’m following you here - it almost looks to me like you’re asking a couple different questions.
Trying to approach this from a slightly different angle:
A formset is an abstraction layer to handle multiple instances of the same form. If you can create a form for whatever, you can create a formset to manage multiple instances of that form on a single page.
Forms can be created outside the context of a model. (In fact, a Model Form is just a special case of a form.)
So I’m getting the impression from what I’m able to understand here is that you might be looking to create a formset supporting a generic form that is suitable for either a Parent or Reporter. Then, when you’re processing that formset, you create & store the appropriate data type from each instance of the form.
Am I on the right track here, or am I missing something?