charcoal Floor\Ceiling insulation in unsealed floor between second story and attic

Hi

Over the summer i am insulating the floor of my attic and the roof of my living and bedrooms. The house is currently only insulated in patches and those patches are themselves now abandoned animal nests. ants (in the styrofoam!) mice and a racoon i suspect. The floor is completely un finished it is just uneven boards laying across the house beams and i want to use this space for drying laundry and some storage so i need to do both at once.
I looked up materials and decided on mostly charcoal with all gaps filled in with wood ash. After having to throw away old styrofoam and rock wool I decided i want to use a material that is ecologicaly disposeable over a more efective or longer lasting material. I do NOT want straw i have pulled out enough moldy blue straw from the walls as is. I think that the mixture of charcoal and ash would be an uninviting nesting place for animals as it is irritating and a dessicant. And lastly ash and charcoal are not so easily ignited as sheep woll and other natural materials though there is no wood stove up there.

Does anyone have any experience with these materials or other ideas?
Cheerrs