Honestly, the “how can Mary be omniscient” line is as stupid and vacuous as the “Can God make a rock...etc.” question.
= = =
NONSENSE.
It quite logically follows the outrageous claim that Mary hears all prayers to her. Whether one fancies almost omnicience or whatever . . . the outrageous assertion about Mary’s listening skills automatically triggers the very logcial response of . . . how on earth could ANY Biblically grounded person ever fantasize such a thing when Scripture gives not the least hint of such on Mary’s part. Further—nor does it give the least hint of such on anyone else’s part including all the Apostles.
I guess they have no spiritual imagination. It's a miracle the Holy Spirit manages to drum James 1:22 into their brains, much less John 3:16. Of course, Christ Himself said, "Eye hath not seen...." I'm sure any decently educated and biblically well-read protestant knows the rest of that verse? From the KJV (even though it's open to each one's individual interpretation).