Lori is too functional for schizophrenia. As far as I am concerned, she planned to kill her children, so she could live on their Social Security, other funds. It was planned, calculated, premeditated and deliberate.
I think that it had been hurried up though, it seems like maybe Tylee was ready to bolt, with JJ. And she was killed before they had actually planned her death.
I think that Lori lived in some fantasy, where no one would ever know or bother her about the children. She almost got away with it. I believe that if CD and LVD had left the country, for a place with no extradition, she wouldn't be in jail now.