You are correct, not everyone claiming the name Christian is one, but the individual who accepts God's Grace and the Gift of his son can easily and truly claim the name, .
As far as Amos as well as the two prophets you mention, when that time comes, those will be fulfilled, and in the fullness of time it will happen, but not quite yet. And modern churches do not teach that there are no more prophets, indeed that was a topic of discussion in a class at my church some months ago. Indeed God has spoken through many great Men (something you acknowledged)
What I will tell you is that when the two prophets, or any others for that matter, come, like those before them, they will bring us God's Word that will be consistent as it has for the entirety of man's relationship with the Almighty. There will be no radical departures, no hard turns to the left or right, no complete changes to the nature of God or his plans. There will be no need for “new revisions” to God's already existing word, for like all those before they will be a part of the ongoing story of the work of the Lord in our lives.
So I am not teaching against any true prophet of God by any means, indeed quite the opposite, I fight to expose those who claim that title for their own ends, those who take and twist and revise God's word to fit their own purposes, not his. I fight against those who claim the title and name of Christ all the while redefining the already defined in a effort to promote and support Earthly desires. That is a place I am proud to be and a position I am finding easy to defend simply by using their own words.