The net result is that neither by itself nor with other things we know can evil render God's existence impossible or even improbable. There is no good evidential argument from evil against theism. Evil may create a religious problem for individuals, but that requires pastoral care, not philosophical discussion.
I think I went into this book expecting much more of the pastoral/religious side of things. Which has made the whole philosophical side of things seem rather dry and pointless. I've never been a fan of theoretical philosophy even while it sets the base for what I consider to be important.
This has also made me realize that when I, and most people, ask "HOW can God allow evil", I actually mean "WHY does God allow...". Feinberg has answered "HOW" in excruciating detail, in multiple ways. I checked ahead and Feinberg does write a whole section on the Religious Problem of Evil. I'll keep slogging through logical theorems until I get to that.