No, the English is "He was with God." There is no second
theos.
Of course there is only one God. That is monotheism and one of the foundations of the doctrine of the Trinity.
Well, it isn't calling the Word "a god" because that means there is another class of gods, but that is polytheism. That Satan is called "the god of this age," means that unbelievers worship and serve him. What is interesting here, though, is that even in 2 Cor 4:4, Satan is referred to as
ho theos.
https://www.jw.org/en/library/bible/kingdom-interlinear-greek-translation/books/2-corinthians/4/
in which ones the god of the age
ἐν οἷς ὁ θεὸς τοῦ αἰῶνος
As for Jesus:
https://www.jw.org/en/library/bible/kingdom-interlinear-greek-translation/books/matthew/1/
Matthew 1:23:
Look! The virgin in belly will have and will give birth to son, and they will call the name of him Immanuel;
Ἰδοὺ ἡ παρθένος ἐν γαστρὶ ἕξει καὶ τέξεται υἱόν, καὶ καλέσουσιν τὸ ὄνομα αὐτοῦ ᾿Εμμανουήλ·
which is being translated With us
the God.
ὅ ἐστιν μεθερμηνευόμενον Μεθ’ ἡμῶν
ὁ Θεός.
https://www.jw.org/en/library/bible/kingdom-interlinear-greek-translation/books/john/20/
John 20:28:
Answered Thomas and he said to him The Lord of me and
the God of me!
ἀπεκρίθη Θωμᾶς καὶ εἶπεν αὐτῷ Ὁ κύριός μου καὶ
ὁ θεός μου.
So, the Watchtower's Kingdom Interlinear Translation of the Greek Scriptures not only calls Jesus
ho theos, it calls Satan that as well. There goes your argument that
ho theos is only ever used of the one true God. In fact, if, as you say, the same translating rules apply, then either the Father, the Son, and Satan are all the one true God, or none are and they are all gods.