We do definitely need to see all the evidence they have, and I hope it's enough, you know? I'm sure there's a lot we haven't seen.
Regarding the items mentioned here, of course Caylee's items will tie in with the Anthony home and Casey, fiberwise and otherwise. But all of these items could have been in the car, traveling with Casey and Caylee, others could potentially have accessed them.
Also, people other than Casey were in the A home at different times, with and without Casey. If Casey were on the computer or phone, even a stranger could potentially have entered the home and obtained any of these items, along with Caylee.
Or Casey could have become involved in the disposal of the body and coverup after a paramour committed the crime (or could even have been left with the body without knowing for sure who did it.) As others have said, obviously if she won't tell, or is unable to tell for whatever reason, I imagine she'll probably be convicted of the murder.
The fact that the tape was left on the face makes me think Casey might not even have been involved in the disposal, though, because I think she would remove the tape (unless the body was already too decomposed when she found it to remove it.)