If he'd been watching/stalking Morgan for a time, and I do think he had been, he'd have seen the cars, the boats, the women, many friends, all money people, beautiful people...
I'll give you some background about the local area. The Oaks is an upmarket pub, but only because it is in close proximity to Mosman. Where he was situated is hardly an affluent area (Neutral bay). It is crowded and I can't see him getting parking permits for boats, let alone multiple cars. If he was in possession of those things then the only way DK would know was by tailing him by car.
Furthermore, he went to the local public school and didn't have a professional job (not that he would know that). He was popular, but he would not have stood out overtly from the crowd. The guy seems normal to me except he hung out with beautiful women.
Maybe. It is also very possible he stalked him while knowing him... and perhaps via watching, he thought he did know Morgan, even if he didn't really.
The crime is not over kill at all if he the type of killer who gains sexual gratification from killing his sexual partner. He will spend the 30 years masturbating to the memory of the crime. He is most likely a psychopath (sociopath these days) and feels nothing for his victim at all. He is not necessarily unbalanced as you say ie. in emotion turmoil or psychotic.That's really a well documented stalker type of mentality. The crime was so much overkill, I cannot see DJK being in a very balanced state of mind. It's not a stretch, IMO, that he thought more was on offer than there really was.
Possibly. More likely he is a garden variety psychopath who felt nothing for his victim.Just to add - there could be years of loneliness, disappointment, frustration, rejection in those 28 stabs and slashes.. says to me a person very much on the edge (and well and truly over it, I should say).