I see your point that most spirits tend not to be complex enough to warrant having been derived from thought impressions, that that they could truly be reflections of inner expectations and anxieties. For example, the three spirits one encounters when obtaining the Titan Shield orb with their power and hostility could have been projections of Duvalier's frustration from a feeling of lack of progress with his attempts to rescue his parents and help his home city.
On the other hand, I would like to think that some spirits have complex enough pasts and memories that they were derived from actual personae, such as Rajav, Luca, and maybe even Iblis.
I guess what's hanging me up on the idea that the spirits are purely projection of subconscious is that Duvalier doesn't find them everywhere. He consistently finds them in hidden, enclosed spaces, for the most part underground, in places where one would naturally expect there to have been deaths, and thus ghosts. So while the idea for the most part appeals to me, I think there has to be a separate trigger for the creation of spirits. Given the spirits' nature of being humanlike, and professing to be deceased, I find it to be a likely explanation that the "trigger" for the creation of the spirits, in conjunction with Duvalier's subconscious desires or anxieties, is Psy-linked traces of the dead: i.e., thought impressions.
So while for some ghosts, the actual deceased individual may not play a huge part in the created spirit, as with lesser ghost fights, where Duvalier creates them in a generic adversarial role, my suspicion is that the individual plays a larger role in other spirits, particularly those having more of a personality.
On a somewhat different note, do you suppose it is those spirits whose identity is more closely drawn from the deceased that have a greater chance to become a jinn?