Book #2. The Silent Partner, by Terrence King.
Homer is a defiant (but not fallen) angel, with a smart mouth and a shaky opinion of God. But when he brings her out of isolation for a critical job on Earth,she ends up wondering if humanity is worth saving.
Her mission is to help a struggling magazine columnist get his novel published. The problem is the ending, but if Homer can get him to change it, and then get it published, it may just change the world. But God is pretty picky about humanity keeping their free will, and so Homer is stumped as to how to accomplish her mission.
The scenes with Homer are the strength of the novel, and King's portrayal of God is both interesting and surprisingly reverential. The theology of free will is also an interesting plot point to choose.
Unfortunately there are too many other plot threads going on besides Homer and Tom, and some of those are a bit too meandering or disconnected to the main storyline. But the characterizations of the leads, and the snappy dialogue, keep the book moving at a nice pace, and make it an enjoyable read.
As with most independently-produced novels, one more editing pass would have come in handy, but it is much better terms of grammar and syntax than the vast majority of DIY books I've run across.
Source: From the author, in preparation for a potential interview on the Book Guys Show.