I use the powder as it is readily available, cheap, and has a lot more surface area for extraction. I doubt you'd need to go a week - a few days will do. I don't know how long it would take for bits.
I would not mix the cinnamon infusion with the hydrogen peroxide, as it seems likely the cinnamaldehyde would be oxidized, leaving something unknown.
Increase the airflow, open the vents, put in some fans...stagnant air is what causes mold. Don't bother with nasty chemicals, their usefulness is (oftentimes) questionable and are harmful to your health.