In Prison Island Break, numerous unnecessary but otherwise interesting characters have died rather awesomely. But the author regretted the presence of Nate Morgan so much that she didn't even give him a last-day-on-the-job scene. Anybody remember Nate Morgan? Of course not.
Inquerius seems to have disappeared completely after the first story in My Little Unicorn. Explained in the Deviant ART version that she retired after the end of Season 1.
In the Skyhold Academy Yearbook series, practically every major character from the Dragon Age series - as well as several minor ones - manages to appear somewhere, if only by mention. But at no point in the series is there so much as an allusion to Anders. It's open to reader interpretation as to why; either those who knew him refuse to mention him, or he simply never existed at all in this AU. According to the authors, there's such a wide schism in the fandom about whether or not his actions in the second game were justified that they didn't feel there was any way to include him to everyone's satisfaction.