This is, bar none, the most extensive, interesting, detailed bits of worldbuilding I have read in a long, LONG time. The way you described how nymphs work and their roles in society is incredibly fascinating and make the world of the Network come alive even more. 
Marie is a character I'd love to see more of, along with Brogan. Does she know when her feathery episodes are going to hit (like do they come on Sundays and Wednesdays from 9-5), or are they completely spontaneous?
Neridia sounds utterly adorable.
When you say nymphs who are transplanted are "unstable" do you mean they get "brain damage" as it were? Is that why she doesn't speak hardly ever, or is she just that shy? Also, how did her captors end up capturing her in the first place? Can't nymphs dissipate into magical energy when they want to? Also also, why does she choose to appear to everyone as a young child (at least, that's what her human form most resembles, but I could be wrong)? Don't they appear as what the person/being observing them most wants to see? Or do they have "default" forms, as it were? Her relationships with Shad and Eric sound adorable, though. 
I'd love to see her interacting with either/both of them if you ever get the inclination. 
Lastly, James is shaping up to be a fascinating antagonist, to be sure (that last line tho XDDDD). The idea of your bad guy literally being a sentient volcano is incredibly badass, though I'm sure he'd give it all up in a heartbeat if it meant he could be human again. He's sure to be something of an oddity among the denizens of the Network though, even among all the weirdos who already inhabit it; is his, er, predicament common knowledge among the general populace (i.e. "Poor sod traded places with an igniad, can you believe it?") or do they all think he's just an enterprising nymph who also happens to favor taking on a male form? And oh no, poor Eric!
Would having all that magic constantly leeched away from him be painful, you think? 
An interesting plot twist to be sure, though. It'd be so cool to see you develop it/James further!
Marie is a character I'd love to see more of, along with Brogan.
Does she know when her feathery episodes are going to hit (like do they come on Sundays and Wednesdays from 9-5), or are they completely spontaneous? Neridia sounds utterly adorable.
When you say nymphs who are transplanted are "unstable" do you mean they get "brain damage" as it were? Is that why she doesn't speak hardly ever, or is she just that shy? Also, how did her captors end up capturing her in the first place? Can't nymphs dissipate into magical energy when they want to? Also also, why does she choose to appear to everyone as a young child (at least, that's what her human form most resembles, but I could be wrong)? Don't they appear as what the person/being observing them most wants to see? Or do they have "default" forms, as it were? Her relationships with Shad and Eric sound adorable, though. I'd love to see her interacting with either/both of them if you ever get the inclination. Lastly, James is shaping up to be a fascinating antagonist, to be sure (that last line tho XDDDD). The idea of your bad guy literally being a sentient volcano is incredibly badass, though I'm sure he'd give it all up in a heartbeat if it meant he could be human again. He's sure to be something of an oddity among the denizens of the Network though, even among all the weirdos who already inhabit it; is his, er, predicament common knowledge among the general populace (i.e. "Poor sod traded places with an igniad, can you believe it?") or do they all think he's just an enterprising nymph who also happens to favor taking on a male form? And oh no, poor Eric!
Would having all that magic constantly leeched away from him be painful, you think? An interesting plot twist to be sure, though. It'd be so cool to see you develop it/James further!