So, while there are gray areas, it seems that the main role Congress would play in an Article 5 amendment process is the determination as to whether the states legislatures or state ratifying conventions would ratify (or fail to ratify) any amendments proposed by the amendment convention. Or am I reading this wrong? If that’s true, I stand corrected in stating that Congress doesn’t play a role. However, it’s still true that Congress would have no real power to prevent an amendment if the amendment convention method is used to propose it.
Of course, the Constitution does state that Congress is to call an amendment convention upon request by 2/3 of the states. From the link you posted, it seems to be a mandatory thing; Congress cannot refuse to call the convention. As a practical matter, though, what happens if Congress shirks its Constitutionally-mandated duty and fails to call the convention (I know, it’s a stretch that Congress might not do its duty, right </sarcasm>). Could a convention meet anyway? Would any amendments from that convention be valid?
Concerning your second point, read Post #29.