Ur doin it right! That's a great setup to get you and a friend started playing. The starters are a great match against each other, and the book is the only one you need to play. The other books are fluff and additional models, but every model you buy will come with the stat card that you need to play them, so you only need the books if you want to see exactly what the model does before you pick it up. The only thing I might suggest adding is an enslaved nephilim because it's a great totem for Perdita, but definitely not essential. (Note: I don't personally like terraclips, but they're not a bad way to get started quickly and easily with terrain.)