As to whether JD is a Narc?
It's very unusual for two Narcs to get together. A Narc wants someone weaker they can control, not another Narc.
It's not unusual for a victim of a Narc parent to be drawn to a Narc partner as it's what they're used to & Narcs love vulnerable & sensitive people as they're easier to manipulate & control.
In my non expert opinion the only Narc in that marriage was Amber.
I have yet to see evidence that Depp is one. An alcoholic & a drug addict, someone who got violent with inanimate objects & be verbally abusive.
But I've seen/listened to the evidence of Amber showing signs of being a Narc with her lying, goading, gaslighting, mocking, instigating fights, trying to control him, embellishing, abusing him & she even admitted to physical violence. Her testimony is cringe worthy, she lies, changes her hole ridden story & the pics she gave as evidence are not credible.
Just my opinion.