Re para 2. The Greeks use the term, μετουσίωσις metousiosis to describe the term. Trent did not impose Aristotelian metaphysics in its definition. The word substance was in use long before the West discovered Aristotle, e.g. in the Creed, 'consubstantial'. The word substance denoted what a thing really was, its essence. The Tridentine definition pointed left out the Aristotelian term 'accidents' and referred to these as 'species (appearances)'.
Re para 3. Yes I agree the Old Testament contains revelation. I accept what the Church teaches concerning revelation (this requires a large dose of humility), that both Testaments are the Word of God in the sense that they convey the Will of God for mankind not necessarily always literally: in other words not as historical documents except in some cases when it is obvious such as Acts and St Paul's description of his travels. If I accept the Scriptures as the Word of God I cannot attribute error to them; God would surely not deceive us.