Hebrews 2:9 But we do see Jesus, who was made lower than the angels for a little while, now crowned with glory and honor because he suffered death, so that by the grace of God he might taste death for everyone.
14 Since the children have flesh and blood, he too shared in their humanity so that by his death he might break the power of him who holds the power of death—that is, the devil
I don't think it is that difficult to figure out what aspect of the Son of God changed when he came as man. Read the scripture. It explicitly mentions two things.
1) Made lower, than the angels. His glory was later restored when he returned to heaven.
I think this is the most drastic measure of Jesus' being humbled to a man. At other times in the OT, the Son of God appeared to men and demanded reverence. Not once did Jesus demand reverence and it was only given to him at birth, Mary's anointing, and once after his resurrection, but he rebuked it until his ascension.
2) Made in the flesh. This means his spirit form changed to physical. That means omnipresence goes out the door. It means he was on earth and not in heaven.
While you are arguing about Omniscience, it may have happened at birth, but I believe he got it back. He spoke as one with authority/author/Word. Of course he knows scripture. He could read peoples thoughts. He knew the past and future. He was compared to King Solomon the wisest/smartest man to ever live and deemed greater.
About not having omnipresence and being in heaven, I think this is a clue with the appearance of Moses and Elijah at Jesus' transfiguration. If the point of the transfiguration was just to show Jesus in his greater glory, then why would Moses and Elijah be present? I think Jesus communication with the angels/heavenly access was limited. Jesus is the commander of the angels and I think Moses and Elijah filled in when he was on earth.