Basically, there's two continuities that Willis has written.
The Walkyverse is the first continuity, consisting of Roomies!, It's Walky!, Joyce and Walky!, Shortpacked! (which is... IIRC concurrent to Joyce and Walky!?), and now It's Pregnancy!
Then, there's Dumbing of Age, with the characters from the first continuity transplanted into a new continuity.
Also, when the title is a spoiler, is there really any way to avoid spoiling?