Aren't most of those sources taken from an appendix in the New World Translation of the Holy Scriptures published by Jehovah's witnesses?
I checked three commentaries. All of them held back from a simple equation, but expressed it differently. Probably the best was the note that in this time period, Jewish writers could call someone God without meaning the One God.
From Haenchen’s Hermeneia commentary
John 1:1 (Herm Jn 1): In order to avoid misunderstanding, it may be inserted here that θεός and ὁ θεός (“god, divine” and “the God”) were not the same thing in this period. Philo has therefore written: the λόγος means only θεός (“divine”) and not ὁ θεός (“God”) since the logos is not God is the strict sense. Philo was not thinking of giving up Jewish monotheism. In a similar fashion, Origen, too, interprets: the Evangelist does not say that the logos is “God,” but only that the logos is “divine.” In fact, for the author of the hymn, as for the Evangelist, only the Father was “God” (ὁ θεός; cf. 17:3*); “the Son” was subordinate to him(cf. 14:28*). But that is only hinted at in this passage because here the emphasis is on the proximity of the one to the other: the Logos was “in the presence of God,” that is, in intimate, personal fellowship with him.
Brown’s commentary says that divine is too weak, but still holds back from a real equation, avoiding making his own suggestion by pointing at Nicea. He gives more explanation in his comment on 10:33
John 10:32–39 (AYB 29): Moreover, we must be cautious in evaluating the Johannine acceptance of Jesus as divine or equal to God. As we shall see below in discussing vs. 37, such a description of Jesus is not divorced from the fact that Jesus was sent by God and acted in God’s name and in God’s place. Therefore, although the Johannine description and acceptance of the divinity of Jesus has ontological implications (as Nicaea recognized in confessing that Jesus Christ, the Son of God, is himself true God), in itself this description remains primarily functional and not too far removed from the Pauline formulation that “God was in Christ reconciling the world to Himself” (2 Cor 5:19).
Ayres in Nicea and its Legacy (which you should read if you haven’t, given your interests) notes that this use of God to indicate a subordinate figure continued to the beginning of the 4th Century.
In John 10:33ff the Gospel itself notes this usage.
The one translation no one uses is "a god". John's point is to identify Jesus with God, even if it isn't a simple equation, not to define him as a separate god.
The question of whether Jesus is God may not be as clear as many people think it is, if it's being asked in the first century context. From James Dunn,i in Did the First Christians Worship Jesus:
"The further question as to whether the first Christians thought of Jesus as God (or god) seems at first to take the discussion a step further. But in fact it does not. For just as "son of God" had a much wider range of usage in the first century, so too theos could cover a range of divine status. Philo was able to take up Exod 4:16 and 7:1 (Moses to be as God to Aaron, with Aaron as his prophet) and say such things of Moses as "(God) appointed him as god" (Sac. 9), as one "no longer man but God" (Prob. 43). In John 10:33-36 Jesus is able to respond to the charge that he was making himself God by citing Ps 82:6, "I say, 'You are gods, children of the Most High, all of you'" (referring probably to rulers and judges). And we have already observed twice that Philo did not shrink from describing the Logos as a "second god." So the few NT passages where the term "G/god" is used of Jesus may not be so significant as they are often assumed to be.162"
Of course by the end of the 4th Century, theologians had abandoned this kind of thing, and used God only for the One God (again, according to Ayres).