No, I believe it to be when one is under a great deal of horrorterror influence but that’s debatable, and I’d say no but some say yes.

Yes

Because the Rings are of Void and Life which are Jane and Roxy’s aspects. Heart and Hope are Didk and Jake’s so, scepters.

I don’t think any classpect changes have ever been confirmed in canon; I’ve only ever seen conjecture, albeit popularized conjecture. But even Rose was never stated as undergoing any kind of role inversion, as far as I know.

Actually, Calliope somewhat confirmed the existence of Role Inversion when she said “player abilities may also manifest in ways in defiance with their aspects if they are heavily resistant to their trUe calling. or, if corrUpted in some way by an oUtside inflUence.”

You can read the full theory here.  But in short, when a player is overly resistant to their role or if they are corrupted by an outside source then their role will inverse meaning that their aspect and class unofficially shift to their opposites. Light to Void, Space to Time, Witch to Seer*. 

*This can change depending on how you classify the classes into Active/Passive partnerships

Grimdark can cause inversion like it did with Rose (making her act more like a Witch of Void) but since we’ve only seen one instance of grimdark we don’t know if it inverses the afflicted’s classpect every time.

I can’t find any evidence that Jade thought this.  Although following the theory of Classpect Inversion Jade did act more like her inverse, a Seer of Time earlier in the story.

Nope

Good news everyone! I finally started another read-through of Homestuck, and I’m taking screen shots as I go, so get prepared for some crispy new, fresh-from-the-oven forgotten facts coming soon to a theatre near you 

It wasn’t stated why her hair was white, lime blood was a guess which is why it was followed by a question mark.