I doubt Julie ever met the relatives again after that first fateful day at Goldhanger. Why would she invent the hitman and why would she recall that a glove came off in the fight with Nevill when if in your scenario all she had to do was stick with what was recorded in Robert Boutflour's diary..
She didn't invent the hitman story she was parroting RWB and Stan Jones theory.
In Julie Mugfords "diary" you have RWBs theories about bikes and wetsuits. She either got this from RWB directly or from Stan Jones.
Mathew Mcdoanld tells people he is a mercenary. He also does drugs with Jeremy. On the 20th of August Mcdonald is mentioned in a meeting between police and the relatives. RWB also notes down Jeremy giving someone £2000 believing he is onto something. Ann Eaton believes Sheila was found on the bed with the bible on her chest.
All the above takes place weeks before Julie "comes forward" and when she does what does she say? Jeremy said to me that he paid Mathew Mcdoanld £2000 to kill the family, He got Sheila to shoot herself on the bed and then placed the bible on her chest.
Seriously Steve how can you not see what has happened?