When you work in the field of contemporary lit, that's one of the benefits! We get to write about CONTEMPORARY stuff! And we open doors for ourselves to enter the critical conversation. You can see how the other 3 articles situated themselves in their discussions to learn from them, but also to see what parts they didnt expand on but which you can expand on. When you think the audience is less familiar with the book, it seems to me all that you need to do is quote and or explain more passages before you go into your analysis. As a hopeful contemporary poetry scholar, I have to do the same, since only a handful of us end up having read the stuff I love.
I hope that helps?