God’s material simplicity seems to apply to His 1st level;
His final happiness, to His 2nd;
and His formal goodness, to 3rd. (Thus, to the question, “What is God?” we reply, “Goodness.”)
How does God’s being efficiently free fit into this picture? It applies in different ways to both 1st and 2nd levels.
On the 1st level, we say that God is bound by no laws of operation even in respect to His simple matter. Nothing determines God to work one definite way yet not any other way.
On the 2nd level, we remove all limitations on God’s ad intra omnipotence and therefore on His “pursuit” and enjoyment of happiness.
Efficient causation for God then has something to describe in regard to both 1st-level freedom and 2nd-level power. To be free is to have permission to act, and not even God’s nature imposes any rules or prohibitions on God. To have power is to be able to bring about happy consequences of acting, and God can do so with perfect competence.
God then is free from any either internal or external obstacles to His beatitude.