(in Hebrew the word for God here is plural - not in the sense of multiple things, but like in many other languages the actual word is plural. Kind of like the word sheep - it is singular and plural at the same time)
Incorrect. The singular is "el". The plural version is "elohim", meaning "the lords". It is a trace of hebrew/ canaanite polytheism. There are more remnants of that in genesis, where god is referred to in the plural 5 times, if my memory is correct. One case is when Eve and her dim-witted mate eat the fruit of moral knowledge. god exclaims "“See, the man has become like one of us, knowing good and evil;". Us, precious? Who is us? Why, the other gods, of course. The elohim.
It is known that el and yhwh - the two distinct gods of the peoples of Israel and judah, respectively - were members of a pantheon of canaanite gods which included Baal, Yam, yhwh's wife, Asherah,
and a few other assorted gods who are also mentioned in the OT.
In verse 2 we read that the "spirit of God is hovering over the water." Thus in the beginning the Bible describes God and God's Spirit both active in the creation.
Eh, maybe, maybe not. The word used for "spirit" is "ruwach" and has many meanings.
The possible meanings are, breath, wind, wind of heaven, breath of air, air, gas, vain, empty thing, spirit (as that which breathes quickly in animation or agitation), spirit, animation, vivacity, vigour, courage, temper, anger, impatience, patience, spirit, disposition (as troubled, bitter, discontented), disposition (of various kinds), unaccountable or uncontrollable impulse, prophetic spirit, to name but a few. So for you to conclusively link spirit in this case to the spirit spoken of in the NT, would be to stand on much less solid ground that you represent.
In fact, not all bibles even say "spirit". Some say "a wind".