If you seriously want to target queries like "balls of yarn" or "squeaky mice," you'd be smarter to break these terms off into individual sub category pages and author specific content for those particular terms. Then you create internal links to those sub category pages by mentioning those terms in the "cat toy" top category page page content.
That's important: don't forget internal anchor text links. Everyone is so focused on grabbing external links that they miss the low hanging fruit on their own sites. I've had sites rank on nothing but a handful of external links and heavy internal linking.