NPD and HPD both seem like reasonable possibilities. Although I think if he has HPD, that's not all he has, because the complete lack of empathy and power-tripping shit aren't characteristic of HPD. NPD seems like a really safe bet, imo, because the lack of empathy and the me-me-I'm-the-only-person-in-the-world as well as the absolute meltdowns at negative attention are really textbook NPD shit.
Looking at the disorders and thinking about it I actually agree with you I think. I'm more familiar with HPD so I was more quick to jump onto that but after some reading, I think he has HPD and NPD all at once, some kind of amalgamate of the two. There's a lot he does that could speak to both, so now I think about it, I take back the HPD only comments. I still firmly believe he has it but he certainly has some NPD shit going on too.
On one hand hes willing to go on things like the livestream with Blaire White in which she talks over him a lot and accuses him of being a creep along with a chat full of fans doing it too, and he must have known that it would be overwhelmingly negative to his image. However, he still went through it without him getting angry or having a melt down or leaving. It makes more sense for him to have HPD in that context because people with that like to be the center of attention and rather than blocking out criticism they love to argue over it for the drama. And with his tweets, he keeps making them despite knowing the reaction will be overwhelming mockery and abuse. That strikes me as more HPD than NPD.
The reason he has meltdowns at reporters, in my opinion, is because its an excuse for him to escalate the situation and make it more dramatic and it allows him to be able to get away with calling the police or an ambulance. To my knowledge, people with HPD are actually in fact known to be very dramatic over criticism and to defend themselves fiercely while people with NPD don't like it at all, that is true, but they're usually more calculated with how they go about refuting it and he doesn't seem to be when it comes to the reporters. Also to recap some of the other points I made earlier in the thread - The whole faking disabilities thing and being very sexual and inappropriate is also super common with people with HPD, and so is being gullible which he was with Ryan. Him taking those women to the BCHRT is probably a very big and dramatic event for him which feeds into the whole HPD shit too.
But then on the other hand, there's a lot that speaks to the NPD. People with NPD are first and foremost, utter bullies. They love to hurt others, to demean them to make themselves feel big and that is absolutely what he's doing to all the women he's sent to the tribunal. He loves making fun of immigrants, and he has no empathy for the women who lost their livelihoods and that is a common trait with NPD like you said, lack of empathy. It could also be his idea of revenge towards them because they refused to gratify his sexual waxing fantasies. People with NPD loooove revenge and not only that but he also did get revenge on Blaire AFTER the stream also with the dox, so it definitely makes sense for him to have NPD in that regard. The whole naming himself Jessica after JR told him to fuck off and reported his ask fm could be some kind of weird sexual revenge too but obviously that is more up in the air.
He also most certainly expects favorable treatment, which is why he jumped on the troon bandwagon - being a trans wamen absolutely granted him the special treatment he'd been craving. It meant unlike other males, who would be laughed at and turned away for suggesting a female salon should have to wax them, that he got his very own special army of defenders and court cases and fame. And the pedo shit - could be linked to NPD, since people with NPD have fantasies about having power over others and so do pedos. And they do say that NPD is more likely to develop when an individual receives nothing but praise and no negative feedback, which Miriam has probably given him all his life and still seems to give him judging by her online activities.
Wow I typed a lot... sorry for sperging I just really like being an armchair psychologist about freaks like Yaniv.