I have modified the plugin to show multple page feeds.
Plugin uses simplepie to fetch RSS feeds. While we merge multiple feeds, simplepie sorts the feed by posted date.
Consider we have feedA, feedB and feedC.
If feedB is more active, that is feedB is having new posts than other two, then feedB's posts will be shown.
Thats why you cant see at least one update from the multiple pages.
Now you are able to get the #number of posts you want to show for each facebook page.
For testing this use the following facebook pages of mashable,wikipedia,huffingtonpost,wordpress since they are very active pages with new facebook posts.
your FB-IDs: 158383046174 226893744059755 78969622116207
189613561196580 are not much active.
Replace the plugin file code with this code
Please keep me posted whether it is working or not.