Content for slides of theoretical project
Unfortunately, most slide-based presentations have too many slides, not too few. It is very difficult to find a good balance. Of course, it depends on the time set aside for your talk. If it is 20 minutes or so, you may already be fine. 

However, an additional slide for each Theorem giving the key ideas from the proof might be useful. It could be a sparse proof outline, or just a statement of what earlier work contributes to the proof. 

However, since it sounds like you fellow students have done things that are based on this chapter of the book, it might be even more useful to say something about how this work leads to the more practical things. In other words, not just what are the important theorems, but why they are important to the work that follows. In other words, place that chapter in the context of the larger goals of the group. That will let you add a bit to your presentation and, perhaps, make it more useful.