“It seems to me (as an Evangelical) that the Catholic concern for seeing the fruit of salvation in someones life for we were saved unto good works... is wholly biblical.”
In my personal opinion, I tend to see this concern as not a call for “fruit.” But, rather, a call to join their religion and cooperate in their practices. The scripture sums up the commandments with love of God, followed up with love of neighbor. If it was really about fruit, the Catholics would be happy with us so far as we follow them. But the “fruits” they demand are different and carnal in nature. This is the same demand made by many other religions, especially the cults with a strong church hierarchy. “Fruits” are redefined as obedience to structures and men in authority.
True, but that does not obviate the binding authority of the moral commandments. As Jesus stated: "Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill." Antinomianism - or the rejection of the validity of the moral commandments - is an ancient heresy that Christians rightly repudiate.
Growing up in a somewhat anti-Catholic denomination, I had many false perceptions about the Church. It took many years get a more accurate understanding, and while I do not agree on every point of doctrine, I have a great respect for the Catholic Church.
That is exactly how it works in the Catholic Church. The command to "believe" in Jesus Christ for salvation is defined as believing in everything the Catholic Church declares must be believed in order to be "in communion" with the Church. Only those who are in communion with the Church (the ONE, TRUE church that Jesus established at Pentecost, according to them) can merit eternal life. Slowly, through the centuries, this rule of faith has expanded to include doctrines not even heard of in the Apostles' time nor even the first several centuries after their deaths.
You definitely described the point that, for Catholicism, the only fruit being inspected is that which they decide IS fruit (i.e., going to Mass, Confession, Penance, corporal and spiritual works of mercy, etc.). It's only been in the last century that the hierarchy has acquiesced to the truth that Christians exist in other faith "traditions" besides Catholicism and even that is disputed by the more traditional Catholics, who reject Vatican II, or at least the interpretation of it. This exclusivity is not Scriptural nor does it honor Jesus Christ.