Two I need explaining as well.
17d Theologian was on a slope circling, but lost control (7)
I have a theologian inside another word, to mean "lost control" overall, but I don't see why my other word is "on a slope"
19d One may ultimately make harmony (5)
I have a word meaning "make harmony", but I need the "make" for one of the letters - double-duty? I don't think the def. can just be "harmony", as my word is a verb, while harmony is a noun.