First: The D&D alignment system is actually kind of terrible at describing nuanced, three-dimensional characters. I have my own spin on it that makes it more useful.
I think the Good-Evil axis in D&D is best understood as Selfless-Selfish. Evil D&D characters generally aren't soulless and don't go around doing bad things for no reason, they just care more about themselves than others. Good characters may become adventures to make the world a better place; Neutral characters may become adventurers to achieve a goal; Evil characters may become adventurers to get something they want. Good characters are the most likely to go out of their way to help or avoid harming others; Evil characters are least likely to go out of their way for anything.
The Law-Chaos axis may be better understood to indicate a character's relationship to the status quo, including but not limited to government, society, and other external authorities. A Lawful character will actively avoid rocking the boat and will use the current system to achieve their goals; a Chaotic character isn't happy unless they're making waves.
With that in mind:
Jenni is Neutral Good. She wants to help people no matter what it takes, and chafes at the restrictions she's under in the PPC even though she understands why the rules exist and should be followed. Usually.
Supernumerary is Lawful Neutral. Doing what's Right is more important than being Good. He values facts, logic, and the Way Things Are Supposed To Be, possibly because it's hard enough living with his brain without people going and messing things up around him. People are messy, and he doesn't go out of his way to interact with others either to help or to harm, though when the chips are down, he does show up for the few people he values in his life.
Ilraen is Lawful Good, but more Good than Lawful. He believes in the virtue of rules and structure, but only insofar as they actually make the universe a better place. If the rules are hurting people, he'll work to change the rules if possible, but mostly he'll try to help the people. In the present day, he's an agent trainer, because he can't change Upstairs, let alone the Narrative Laws, but he can help new recruits be better prepared to handle things than he was.
Derik is... complicated. He believes he's Lawful Good, but he's actually Chaotic Good—and that's not because of his issues. He comes from a culture in the throes of a sea change, and he was totally on board with the change. Also, he has a history of taking justice into his own hands from a young age and doesn't really respect any particular authority that isn't his own. It's not that he disrespects authority or can't accept leadership from others, but if he thinks the people in charge are being stupid, he will ignore them and do things his own way. His willfulness has gotten him into pretty much every bit of trouble he's ever had in his life, up to and including his recruitment to the PPC.
Gall is Neutral Evil. Her guiding principle is "What's good for me," and she will do precisely whatever it takes to get what she wants regardless of who she has to step on to get there. She respects strength over any sort of moral or civil authority ("might makes right"). However, there ARE lines she won't cross. "Evil" does not mean "must always do the worst thing possible": she's not going to burn down the Nursery (except maybe by accident if a visit with Fellrazer gets out of hand some day); she's not going to murder someone if she can just punch them; she won't betray her friends; she would never force anyone into her bed. It's just... less that it would be wrong, more that it would be more trouble than it's worth to her. Developing feelings for Derik and having a kid is forcing her perspective to shift a bit, though. She could end up True Neutral, maybe even Lawful Neutral.
~Neshomeh