Yes, hair gets everywhere, especially via the floors, bedding and simply being in a washing machine.
I am kinda fuzzy on the timeline atm, but wasn't their own kid in a similar age to the killed toddler at the time of the murder? This could not only explain the possible remorse behaviour with the kid (wrapping etc), but possibly also the hair - post-partum hair shedding is a thing. Mentioning it just in case if the murder victim with most AE hair found was murdered during the first lifeyear of their daughter, not that it really needs an extra reason, but just an interesting biology fact.
I am kinda fuzzy on the timeline atm, but wasn't their own kid in a similar age to the killed toddler at the time of the murder? This could not only explain the possible remorse behaviour with the kid (wrapping etc), but possibly also the hair - post-partum hair shedding is a thing. Mentioning it just in case if the murder victim with most AE hair found was murdered during the first lifeyear of their daughter, not that it really needs an extra reason, but just an interesting biology fact.