She's a Cabossian, a bipedal species with two genders and two separate types of existence. All that matters on Caboss is if you're sterile or fertile. Untrustworthy solely takes place off Earth, and the characters have no inkling that humans so much as exist.
I wanted at least one character to be a bit overweight, so I essentially elected her to the task. Because the first seven or so chapters exist to foreshadow much of the rest of the story, her weight does the job admirably. For, who to better contrast with starving characters than an overweight one?
Consider how NaNoWriMo can also affect how we write. I know it affects my own work. Wanting to make word count at all costs can mean front loading a book. It can also mean oppressive dialogue and extra characters. Meandering is great for word count. But it also adds to chapter length. And it's often the kind of addition that isn't necessary.
Like other characters named Shapiro, Marnie is a callback across universes. Her middle name, Robin, ties in with Robin McKenna, a pivotal character in the Time Addicts series. Marnie is also a Bostonian, although I don't outline that well enough.
Give it one last read-through. Look for the right words in the wrong places (e. g. a typo which turned out to be a correctly spelled word, so spellchecker missed it). Look for sense and ease of understanding. Make sure your plot makes sense.
I've often heard that, to succeed, you need to visualize success. But I don't do that. Rather, I visualize failure. And then I do everything in my power to avert and avoid catastrophe.