the parallel often ignored is first born of creation, first born of the dead. seems clear enough that protokos [firstborn or pro-type] has the meaning of the very first one raised to immortality and thus first born of all creation would mean first of all creatures. as to all things vs all [other] things, this is not an unusual construct, in another verse Paul says that God subjected ALL things to Jesus, then he clarifies with the obvious exception of the ONE who subjected all things to him.... and then he makes the conclusion that once Jesus has brought all things back to perfection he will turn it back over to God so that God may be all things to everyone... which is complete non-sense and idiocy if Jesus already IS GOD.
as to other god[s], the bible calls Jehovah the El Elyon, the GOD of gods and angels were viewed as part of the Elohim or gods.
note too that trinitarians often overlook that they claim God is three who[s] but ONE what... yet the bible clearly says that Jehovah is God alone, that HE [not THEY] is the ONLY TRUE GOD and Jesus called him the very same thing in John 17:3.
When Jesus said I and my father are one -- I and the SOURCE of me are ONE... the jews assumed that he was claiming to be either EQUAL to GOD or GOD incarnated....[john10] yet the response of Jesus was not to acknowledge their claim and agree with it... far from it, he turned it on them and showed them according to psalms, all those who seat themselves upon the judgement seat are called God[s] because they are acting in the authority and power of God to judge life and death... here they were accusing Jesus of blapheme because of claiming to be one with GOD yet they were not doing anything different by claiming to be Judges of life and death and thus making themselves guilty of what they falsely viewed as a crime in the first place.... so if Jesus were guilty of a crime, so where they... but Jesus goes further and says, he never claimed to be GOD, but only God's son. [which all Jews thought themselves to be as part of Israel, my first born]
--beyond that, check out EVERY vision of heaven given in the bible, like Daniel, Acts, and the Revelations... three witnesses from heaven which agree-- that there is always ONE upon the throne called Ancient of Days, God and THE LORD GOD...and another [not two others] with him.. the son of man, Jesus and the lamb, the lion of Judah who is Jesus.... there is NO vision of heaven which says different, NO vision which has the holy spirit as a person, infact revelations has it as 7 bowls of fire and seven angels who carry out the will of God... acting as his eyes and hands... it is even called the finger of God in the gospels.
this also agrees with John 1:1 which has ONE GOD and the WORD [no Holy spirit person] and 1Cor8:5-6 which showed that in comparison to all other god[s], there is to us [chrisitans?] but ONE GOD, the FATHER and one LORD Jesus.... again NO holy spirit mentioned as a co- anything.
Personalizing the HOLY spirit makes sense in context with Revelations which again shows that it is seven angels which act as the eyes and hands of GOD, but are NOT themselves GOD but speak for him and in his name, as in the ANGEL of the burning bush who spoke AS Jehovah.