The Council of Nicea did nothing but distribute Bibles. Jesus' 'divinity' was a foregone conclusion within 1 year of his execution. The 'vote' only decided if Jesus and YHWH were the same substance (homoousious), or similar substance (homoiousious). Out of over 300 Bishops in-attendance, 3 voted for 'similar'. 'Homoousious' was the view of the original Apostles and supported by the text of the OT.
The significance of December 25th is that it is 9 months from March 25th which is the date commemorating Jesus' conception (Feast of the Anunciation). This is attested by Tertullian in 200 CE........a century BEFORE Christianity was legal.
The Psalms chapters aren't 'stolen' from any other civilization.
Ezekiel's Wheel represents a Babylonian chariot wheel since there are multiple instances of it appearing in the iconography of the region. At least you don't think it's a spaceship.....LOL.
All the Egyptian stories were copied FROM the Bible. None precede it.
As far as what is in the Qu'ran, I'll leave that to the Muslims who know the text better than I do.

in your delineated order:
False. The council of nicea, organized compelled by pagan ceasar Constantine, compelled the early church to abandon all 'jewish' customs, including Saturday worship and keeping the law of moses, officially creating Christianity as it is known today. the council successfully merged existing pagan tradition with key terminology and elements of the Hebrew bible, created a warped religion based on the love of Messiah, but not obedience to Him.
false. the significance of dec 25 is far older than whatever roman council decides and also is pagan, dating back to Babylonian sun worship, the winter solstice. Following catholic excuse for pagan worship is akin to following catholic excuse for mass excused pedophilia
true.
false. Ezekiels wheel isn't representative at all, it is real interaction with spiritual beings. Since spiritual beings, both good and bad, have been appearing to civilizations for the whole of mankind, the similar occurances do not indicate 'borrowing of culture' they indicate two corroborating witnesses to what spirits actually look like. Ezekiel was surrounded by Babylonian and gentile influence, which he was himself rejecting directly in scripture, so to borrow 'iconography' would be completely contrary to the doctrine he was upholding. spirits sometimes manifest themselves as wheel-like beings, this is also documented as 'ophanim' in the hierarchy of angelic beings.
True.
and...I also no nothing about the Koran, aside from the jinn