There is a lot of overlap between sociopaths/psychopaths and narcissists. Much depends on what triggered them and what motivates them to step over into the dark side. There is callous manipulation, extreme self-centeredneas, exploitation, and lack of empathy.
Psychopaths: more likely to hurt others for specific purpose (eg get rid of witness). Narcissists: more likely to hurt others when their ego has been hurt (eg in response to “losing face”).
I can see PF fit into both. Alternatively, he might have lived fairly “normal life” until Sept 2018, when he might also have sufferered significant psych issue (like something happened which made him snap). It was in Sept when it was reported he first started soliciting for murder.
Also, personality disorder by default is “pervasive” and long term. It isn’t a sudden change in personality at age 30 or so.
Should maybe mention I’m a PhD clinical psychologist. Not that it makes me qualified to dx PF since he isn’t my client (in which case I’d have zero time to be on WS and speculate and discuss with other fellow WSs)!! I’d feel I was missing out big time