For apologetics, you can’t go wrong with Peter Kreeft:
Handbook of Catholic Apologetics
I always find Kreeft to be very readable and engaging. Note, this book is virtually identical to Handbook of Christian Apologetics. The only difference is the former title has an extra chapter at the end on uniquely Catholic issues. The bulk of the book is applicable to all Christians.
I second the above recommendations on Vatican II, particularly with going through the documents yourself. Flannery is the most widely circulated translation, and you can find copies of them for pretty cheap. The blue one includes related post-conciliar documents, while the green one includes just the 16 core documents and with revised, inclusive language. So I generally recommend the blue one. Or you can go with the Abbott translation, which I think is generally better, though it is harder (at least for me) to find a copy that is in decent shape.
I also like Dr. Alan Schreck’s Vatican II: The Crisis and the Promise. The Ratzinger Report, though from the 1980’s, sheds some light on the aftermath of Vatican II from a man who was there and would eventually become pope.