Judy Hicks
*minor spoiler*
Apparently one of the teenagers is her son. Which means he would've existed during 4. Now, nothing was explicitly stated in 4 to make his existence impossible. But I always more got the vibe she was single and childless. Even being duty-first, I feel like it would feel more organic to have mentioned him. Even a throwaway line about how he's with a baby-sitter or she sent him out of town. But small thing, I know.
Also, just to throw a curveball at us, and reflect real life a bit, I wonder if maybe we'll find Dewey and Gale are quits, and now he's with Judy.