As to these Mary issues, I agree that the scripture is not alone sufficient to teach about her lifelong sinlessness and virginity; we don't teach that from the Bible but rather from the Holy Tradition whence the entire knowledge of Mary and her life comes.
Evangelical Christians largely affirm the canon of Rome and core Scripture truths both agree on, but I hope you can also understand that evangelicals typically experienced a dramatic transformation due to trust the gospel of grace preached from the Scriptures, after having been in churches where it was not really preached nor the Bible was emphasized. Due to that and their resultant Scripture and relationship centered faith they are alarmed at doctrines which lack Scriptural warrant and militate against it (such as praying to departed saints) and which much depend upon tradition and the infallible magisterium.
The standard of the Sermon of the Mount, and generally the standard of divine perfection in Matthew 5:48 applies to Catholics. In fact it applies to everyone, the Protestant just think they can avoid applying it to thmselves through their sleazy "faith alone" maneuvre.
Matthew 5:48 certainly does apply to everyone, and while it is easy to broad brush evangelical faith, the reformers overall did not preach, easy believism, but held that a faith which is salvific is one which shows forth fruit fit for repentance and endures. Recently no less a figure then R.C. Sproul preached, “Since our righteousness proceeds from our justification, which is based upon the righteousness of Christ alone, we must never be deluded into thinking that our works of righteousness have any merit of their own. Yet as Protestants, zealously maintaining our doctrine of justification by faith alone, we must be ever mindful that the justification which is by faith alone is never by a faith that is alone. True faith is a faith that manifests itself in righteousness exceeding that of the Pharisees and the scribes, for it is concerned with the weightier matters of the law: justice and mercy.”
The issue is what perfection means, and its attainment. What the Bible most clearly teaches is that true believers, for which faith is not a one-time deal, are declared righteous and thus practice righteousness. While they do not attain unto complete perfection, as Christ is perfect, they are not only positionally made “to sit together , and heavenly places in Christ Jesus,” (Eph. 2:6) but upon death they “shall ever be with the Lord,” (1Thes. 4:17; 1Cor. 15; 2Cor. 5:6-8) and will be made like Him when He appears, (1Jn. 3:2) but who show yet judge the quality of their works. (1Cor. 3:8-15; 2Cor. 5:9-11) More could be said, but I am trying to be brief
I also agree that if one talks to a regular Evengelical about his faith in matters of immediate importance to him, -- moral life, etc., -- A Catholic will not find anything to argue about. The Evangelical distinctives: the total depravity of man, the irresistibility of grace, the limited atonement -- are all, to a Catholic mind, some kind of German philosophical voodoo, that is far from the Gospel and makes little sense, but luckily is not something anyone can really practice. And we are very much about practice. So far, no Evengelical Church taught its flock to do bad works, although I think that that three-car-garage-prosperity gospel guy comes close.
The issue is what perfection means, and its attainment.
Yes, it is. See the Church is here as a hand of God. The Catholics do not think they are saved by being nice people anymore that Protestants do. It is by that hand, to which I bow every Sunday, that hand that holds Him and puts Him in my mouth that I am saved. I want that for everybody. So, read the Holy Scripture adn remember Who gave it to you, -- and reach the right conclusion, please.