If Jesus was not God Incarnate in the womb, then humanity is not reconciled to God. You also have to deny Scripture when Elizabeth referred to Mary as the mother of her Lord, and considered it a great blessing to be visited by her.
If you think God can physically live inside someone and not alter them -- sanctify them, then how little you must think of His power. If the temple itself sanctified the gold, as Christ said when He was chastising the Pharisees in Matthew, how much more would God Himself sanctify the womb that bore Him?
And Samuel, Revelation, Hebrews, and Christ Himself beg to differ that the departed don't know or care what's going on in the earthly realm.
Christ Himself said God is not a God of the dead, but of the living. Samuel knew what Saul was up to, Hebrews says we are surrounded by a great cloud of witnesses (remember the Hall of Faith in the preceding chapter--supposedly long-dead people), and Revelation talks about the prayers of the saints. Who are they praying for? Themselves?