I think he went a little farther only to say that he had come home and found Melissa using the stun gun on Kelly and so he beat her ass; later he says they found her dead of an overdose.
yeah, pretty accurate. Explains the multiple tazer firings. Maybe he'll say there was a big struggle when he caught MJ zapping her, she was on drugs, and she died in the struggle.
They panicked, and decided to dispose of body.
Melissa took the plea with everything on Craig so they're sure she'll be out in 5 with time served.
Craig knows it's all or nothing - he gets 20 years, and he'll never see daylight again.
He wants a trial now, and most of us would probably do the same with the same options.