I have mixed feelings about this story.
On the one hand it's very well written and all the characters actually feel in-character, which is something that even some of the best stories struggle with a lot. Your additions fit in with the canon plotline (with a few exceptions, I'll get to those) and everyone's reactions to the extra stuff makes sense. What's more, all the extra stuff with the Rachni is actually rather compelling, making you want to keep reading to see what'll happen next. Normally I don't really like it when writers and artists bolt dicks to female characters who we know didn't have them canonically, feels like the easy way out, but by first providing an in-universe explaination for why Shepard has a dick now and then having her react to it in an in-character manner I felt you'd saved it for me.
However, and here's the rub, after a certain point the story starts to meander. Around about Subject Zero, I think. You start introducing more 'porn tropes' unrelated to the Rachni plot, like the usual fandom cliche of having Kelly be responsible for the scale-itch outbreak, or that Jack has a penis.
The fact that neither of these are really questioned by the characters breaks the sense of immersion you'd managed to create by having everyone react in a way that made sense beforehand, like how Shepard starts making her own covert inquiries to see if her new package is due to Cerberus fooling around, and cause the story to lose its compelling driving force that the Rachni drone had introduced.
There's not really much of an explanation as to why the drone vanishes for a few chapters, and when it shows up again only to be vented out into space it feels almost cruel. I was gutted that the drone never got to fuck Miranda, as you seem to have been indicating would happen, and I feel like its abscence going forwards makes all the 'rachni DNA/pheremone' stuff harder to swallow (fellatio joke in there somewhere).
I was totally on-board with the idea of this thing covertly scurrying around impregnating people whilst Shepard deals with her own present from it, however that's done, but to so abruptly slam the door on it and just leave us with the futa plot plus all the other stuff feels like a wasted opportunity.
Speaking of wasted things, I don't know why I'm making this review, considering the story's been lying fallow for the better part of four years, but I guess I felt that such a promising work as this was worth the effort. I hope this helps you.
Was amazing and I hope there is more to come!
Gabby is turning out to be what I thought Shepard was going to be. I was hoping Shepard could have been the breeding machine as my shep has my face, but Gabby is cute, I can deal with that. I have no idea what Shepard's Rachni side is meant to be doing at this stage.
Again, I hope there is more soon!
Kind regards! Amy x