This seems fun. :D Oddly enough I don't have a lot of artistic characters but I'll give it a shot.
Both versions of Nimue Jakande would have the oddest "style" to their portraits on account of being technically blind.
As for medfant!NImue Jakande I actually have this picture from 2009, from a scene where she got a chance to try out painting for the first and only time. It wasn't supposed to be an autoportrait at the time, rather an attempt at depicting the White Walker-like baddies in her roleplay, but an actual autoportrait would've looked very similar (though possibly with no "eyes"). She'd never experienced light and shadow at that time, and only experienced color once (when encountering the aforementioned baddie). She could sense auras, but it had little to do with vision, being more akin to "feeling" or touching a person from every angle at once. Thus when she tried to draw a head she...essentially couldn't choose an angle and thus just made a vague blob, like trying to depict it from all angles at once.
Contemporary!Nimue Jakande would fare a bit better at the start of her story. Having been more familiarized with how faces are "supposed" to look from engravings and other sources she'd probably submit the most generic face imaginable when asked for an autoportrait.
As her powers evolved however she kinda became able to "feel" things like phone- and computer screens, so she would've been able to work on an autoportrait using her phones' screen to see how her face would look. I'd like to imagine that her "style" would completely lack linework, instead be made up of blobs of color, possibly without her quite understanding which part of her face she's currently working on. It would also escape some of the typical "newbie" mistakes because the usual visual shortcuts for how a face is "supposed" to look like haven't been programmed.
Parable of the Cave is another whose style would be interesting. She thinks she's The Best Artist out there, with her style being very tribal, striving to give forth the "idea" of a creature in as few lines as possible. No shading. No perspective. Just geometry or continuous lines.
These are her default ways of depicting a "human". In her culture a person is not distinguished in art - rather art is there to distinguish the person (as most of the art in her clan is in the form of glowy tattoos which they use to tell one-another apart at a glance in low-light environments). Were she to start adding specifying elements, such as tattoos or facial features, it would defeat the goal of geometric simplicity. Thus this is how she would draw herself. The same as others. With the mark which means "Human".
I didn't quite manage to capture the autoportraits of Julia/Henry however I think I created something truly terrifying in my attempt and I want to share the nightmares. :D
S/He wouldn't pay much attention to hir actual facial features - such as the shape of hir eyes and face, downplaying the pointiness of hir nose. A lot of attention would go towards tertiary sexual characteristics, such as clothing and makeup. S/He sees hir default appearance as a base on which props are to be applied, thus the latter is more important than the underlaying skeletal structure.
Hir actual drawing skills are better than depicted. S/He's got a good eye for detail, just no artistic education (thus falling prey to the usual visual shortcuts the brain tries to force one to take). S/He's also got a very steady hand so I feel like an actual drawing s/he makes would actually have quite the neat and confident linework.
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