Why do you assume Mary could only know our thoughts if she were a deity? That’s rather a large leap. Couldn’t it also be that if she hears our prayers and petitions, either aloud or by thought, it’s only by power granted to her by God? Don’t you think God would have the power to do that? And if He does have the power to do that, what makes you so certain He doesn’t grant that ability whenever someone asks for Mary’s or another saint’s intercession?
Also, the fact that you would dismiss and boil my points (they’re not even really my points, as this was all hammered out far before I existed) about Mary being the Mother of God down to “faulty reasoning” without even bothering to take the time to look at historical sources and open your mind to another viewpoint, even if you ultimately still don’t agree with it is…well, sad. You’re missing out on so many rich sources of insight and teaching from early Christians.
No, the term “Mother of God” is not listed, black and white, in scripture, but neither is the term “Trinity”. You believe in that as a Christian, don’t you? That was also a term coined later at the early Christological councils in response to teachings that were being challenged by heretics. And yet, while that word is found nowhere in scripture, the teachings in support of it are.
What’s really extra-biblical here is the belief in scripture alone. Nowhere in the bible can you actually find that term, ‘Bible alone,’ or even the teaching that we should guide ourselves by the Bible alone. The New Testament didn’t even exist in written form for quite a while after Christ finished His mission here on Earth. The apostles and Christ’s followers handed on their teachings orally, just as Christ did. 2 Thessalonians 2:15: “Therefore, brothers and sisters, hold fast to your traditions, whether by word of mouth or by letter.”
It certainly doesn’t seem as if scripture supports the Bible alone philosophy. But I doubt I’m going to convince you anyway, so I’ll bow out before we derail the OP’s thread any further.