My gut instincts and experience (from researching British Museum Newspaper Library) are that early reports and police investigations tend to be more accurate than late PR, political and defense spin. I have mentioned this before.
For example, if you want to understand 9/11, watch the developing news broadcasts.
That's not to say the reports are accurate, but tend to be more true on an emotional level.
Think about it, history books are written by the victors. Go to a newspaper library to find out the story, before the victors won. That gives you a better over view.
In this case, you have a brutal murder. Police have to think on their feet. Faced with a stab in the neck, the police profilers will tell them they should be looking for a man, as female murders by stabbing are extraordinarily rare. (cf Jodi Arias, Joanna Dehenny, Tracey Andrews.)
Mignini saw the murder scene, the body and each of the accused in person.
IMV his early theory is more accurate than "row over unflushed toilet". There are lots of depraved sexual elements here, not to mention Kokomani's claim of rehearsal the day before.
That's not to say it is conclusive evidence. That was for the court to decide.