I don't think BB is a great Mother, but I don't believe that she killed Maleah. I believe that there was a huge blowout argument between DV and BB. BB left, and DV took his rage out on Maleah. DV had probably been abusing Maleah for years and BB ignored it.
DV panicked and made a plan to dump Maleah's body. I think that his brother was in on this. And BB knew right away, probably CD contacted BB about not being able to see Maleah, BB tried to reach DV, and he wasn't taking her calls. BB called BB2, who told BB to file the missing person's report.
The police are probably trying to figure out when BB knew Maleah was dead. Or trying to figure out how to charge her as an accessory, for leaving her child with a man she admitted abused Maleah previously. The whole bath scenario was beyond depraved.
What I don't want to see, is that DV says Maleah drowned while taking a bath, and he panicked because he is so mentally disabled he didn't know what to do, so he drives to Arkansas and throws her out the door in a trash bag, blacks out (of course), and in a daze ends up at the hospital.
Oh, poor DV! No cause of death, so 12 months for tampering with a dead body.
Yes, sadly, I do think this is yet another child who has died as a result of abuse. Texas seems to have an alarming number of children who have died this way in the last year. (211) I think they need to work on "the system," and take more serious preventative measures so it doesn't result in such tragedy. (Such as removing the children from the home)
I think the first scenario you described makes the most sense, according to the evidence and what we have learned so far.
Originally I thought she died as a result of the prior injuries and ongoing abuse. If BB knew about it, and failed to seek medical treatment or cover for DV than naturally she is also responsible for her child's death.
But the evidence does seem to point towards DV and BB arguing, him beating Maleah in a fit of rage, then panicking and inventing a ridiculous story to try to get out of it.
That is, if QX's account is accurate.
That they found blood in the hallway and bathroom is pretty strong evidence of this. I don't think he dismembered the body, but I guess you never know.
What is missing, as you say, pertains to when BB was aware that Maleah had died. I don't think she died in that hour and a half while she was in the apartment. I think DV got rid of the body shortly after she died. It doesn't make sense that he would hide the body in the home for three days, and wait until Friday to clean up the evidence. Not with the kids there and not with the risk of CPS or others dropping by at any time. And then of course there would be the smell of a dead body.
BB must have contacted him while she was away. The phone records will show how many times. She must have asked to speak to the kids, or at least asked how they were. He may have lied to her right up until the time of his arrest.
But she had to have known something. The key is figuring out their communication and whereabouts during the crucial time period.
Maybe if we can research some of the other cases of death by child abuse, we can get an idea of what the charges could be. Imo