Again, the worst that can be made of it, as we are given to understand from the story, is accidental manslaughter, which means that somebody died by accident.
The story does not provide any evidence of malice, that is, that the perp intended to affect the result.
A state's attorney ought not to abuse the power of their office by trying to "over-"charge a perp. Charge the perp with what you have.
For bystanders and family members, the worst is the seemingly careless death of the children, but are we to have the prosecutor tack on charge after charge for the sensationalism?
Why not charge the perp with "hate crimes?" That might have happened.
But we do not know enough to support that.
Offices of law enforcement have only the authority to charge somebody with a crime for which there is sufficient evidence to support; all else beyond that, is an abuse of power.
I stop you for speeding; you're 20 over the limit. Should I also charge you with reckless endangerment, grossly negligent operation, drunk driving, etc.?
No, I should not; because you were given to understand from the story I set as an example, only that you had been speeding, 20 over the limit.
We do not have evidence that the mother intended that her children fry; we only know that she was negligent and contributed to their accidental deaths; that's all that the story relates and it is the worst for which charges can be made.