The problem was that all of them were living in the same huse, so it is not possible to say who was responsible for what.
Caylee was found close to the home in association with items from the home.
The stuff from the car was a red herring. If her body had been left in the car the car would have been full evidence of that. The only way to prevent that would have been to seal the body in a water tight bag. But if that happened, the "death hair" would have still been in the bag, not in the car. The implication is that the body was stored somewhere else for a significant Length of time and the hair ended up in the car by transfer at a later date. either that or it wasn't a death hair.
The evidence suggests that the body probably never left the home for a considerable time, and if that was the case, then it could have been any of them. We know that KC moved out and was apparently unaware that Caylee was missing. Then she appeared to be involved in a cover up. The assumption is that KC was the one being protected, but maybe it wasn't her, maybe the protection was for someone else and they just thought they could get away with it letting KC appear like the guilty one but knowing there wasn't really any evidence for that. Misdirection.
The chloroform theory was kind of ridiculous. At the very least they should have undertaken controls to demonstrate their theory was possible but they did not.
If you look at the "foolproof suffocation" search, it was followed 51 seconds later by a visit to a site about suicide, that had nothing to do with methods. So, the search had nothing to do with homicide, but suggests more the idea of suicide. And you have to wonder why. Whatever happened, it was clearly not a first degree homicide.
Everyone I think agrees that something illegal happened to Caylee, the question however is what and who did it? That is far from clear and it is largely the reason KC was aquitted. All of this should have been clear to the prosecution, but they went for a hail mary anyway in the hopes that they could elicit an emotive response from the jury in the absence of evidence. But, as we know, it didn't work and they got nothing.
They would have had for more success with lesser charges IMO.
The death hair was found in the trunk because Caylee was driven around dead in the trunk and wasn't bagged until the 17th or 18th when the neighbor noticed FCA backing her car into the garage.