I have to say after a cursory reading that I don't see how you're getting what you say you're getting out of it. I see no dependence of omniscience on omnipotence. In fact the author is talking about foreknoweldge and predestination. At most, you could maybe see an argument concerning the logical order of decrees, but omniscience and omnipotence are immutable attributes of God. His possession of those attributes is axiomatic. Without either of them, He is no God.
The last line says, "God foreknows the future because God foreordained the future."
Shouldn't it say, "God foreknows the future because God is omniscient?"
The way it is worded suggests strongly the dependence of God's knowledge on his omnipotence. The other highlighted sections add to that interpretation.