God the Father has ordained that we come to Him through His Son.
The Father is not man so He cannot be an intermediary, if Jesus Christ were only a man He could not be an intermediary.
Only as God AND man can Christ mediate twixt God and man.
No.
Jesus Christ had to be and is a 100%righteous man.
Nothing is said of Jesus Christ having to be God to make the atonement. Only that He overcame and rose to the place of God over the new creation.
Rom 5:18 Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.
Rom 5:19 For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous.
What you are saying is that Jesus could not be righteous unless He be God.
Heb 2:10 For it became him, for whom are all things, and by whom are all things, in bringing many sons unto glory,
to make the captain of their salvation perfect through sufferings.
Heb 5:7 Who in the days of his flesh, when he had offered up prayers and supplications with strong crying and tears
unto him that was able to save him from death, and was heard in that he feared;
Heb 5:8 Though he were a Son,
yet learned he obedience by the things which he suffered;
Heb 5:9 And
being made perfect, he became the author of eternal salvation unto all them that obey him;
LA