Two coats of topcoat should be fine. Use a 100% acrylic waterbourne enamel (such as SW ProClassic or BM Waterbourne Impervo). Do not use wall paint, it is not very good for this application, as you will have durability issues and possibly problems with sticking (a.k.a. "blocking").
I can also recommend a mini-roller with a mohair (usually 1/4 nap) roller
The "hot dog" or "weenie" rollers work well in odd spots like bookshelves (and can get into the corners), and the mohair sleeves work well with most waterbourne enamels