@adamj3333 If you have “use Facebook avatars” set, the plugin does pull in the users photo from FB when they make a comment – if they make that comment inside FB.
If they make a comment on the WordPress blog outside FB, they will get whatever avatar your blog uses.
In terms of “working with” Facebook Comments, that depends on what you mean by Facebook comments and what you mean by working with.
Facebook Comments can mean the new offering from FB which completely replaces your comments with their widget – https://developers.facebook.com/docs/reference/plugins/comments/ – or it can mean a WordPress plugin which lets people leave WordPress comments with their FB identity – https://www.ads-software.com/extend/plugins/facebook-comments/, or https://www.ads-software.com/extend/plugins/facebook-comments-for-wordpress/, or https://www.ads-software.com/extend/plugins/facebook-comments-plugin/ or maybe others.
WPBook expects real WordPress comments – stored in the WordPress database, displayed in the context of a post. So long as these other plugins/approaches do that, they will work with WPBook. If they replace the whole commenting system, then their comments will not show up in WPBook and vice versa.
Finally, if these (or any other Facebook related plugins) include an out of date version of the Facebook SDK/client, they may conflict with WPBook, as only one Facebook client can exist in a given WordPress installation.
Trial and error is really the only way to test different combinations of plugins and Facebook configurations at this point