Some cherry-picking...
The Protestant position on faith vs. works is Christological. It is not saying that a "Christian" can have mental assent to the Gospel without any manifestation of that in his life. Faith is not faith if it does not beget works.
The Protestant position is that God's grace alone is sufficient to save, and that any works with come forth as a result of the believer's becoming a new creation (Galatians 5:17) were prepared by God in advance anyway (Ephesians 2:10). The point of salvation by faith alone is not to give the prospective believer a "Get Out of Free" card without having to be obedient to God in everyday life, but rather to ascribe all the glory to God in the act of salvation, and none to the works of man.
In my observation, the difference can be whittled down in a nuts : Catholics believe works are a necessary element of salvation, while Protestants believe they are necessary evidence of salvation, i.e. Matthew 7:16.
Well, it doesn't say that. Romans 1-19:20 contradicts the notion that the Bible alone presents the revelation of God.
However, the Bible does say this: "All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the man of God may be thoroughly equipped for every good work." (2 Timothy 3:16, NIV) And the words for "thoroughly equipped" in Greek are "artios exartizo," from which we are meant to understand that Scripture is sufficient.
This does not mean that Christians should not aspire to hear the teaching of others regarding Scripture, for not all of it is easy to understand (2 Peter 3:16). Sincere Protestants would have no interest in solid expository preaching, nor in studying the Bible together, if they thought they knew it all by themselves. The difference between Catholics and Protestants is that Protestants are not required to take such instruction as binding. The example provided to us is that of the Bereans (Acts 17:11).
I believe that the Bible allows believers to disagree on certain matters of doctrine without severing fellowship (1 Corinthians 14).
Because of verse 63.