What is necesary for faith WC? Why do so few believe?
Because I know you to be a sincere Christian, I will take the time for a response. Those are two distinctly different questions.
All that we know of the nature of the faith required is that it be belief "in" Jesus Christ, presumably as opposed to "belief about" or "belief in the teachings of,,,." However, we don't know that there are any particular doctrines incumbent in that definition. I think the reason for that is that God is the judge of the heart and there is no appeal. So, He can well and truly decide whether a given individual has so fully placed his faith "in" the Person and Work of Christ as to meet the test. We know that this kind of faith is preceded by 'repentance', that is a true sorrow for our past sins and a desire to turn from them. Now whether that is part of the faith in Christ or a precondition to it is a distinction without a difference.
I think that there is also an element of "unreservedness" in such a faith. That is, it is not a conjunctive faith, not a faith in Christ and Bhudda, or Christ and Mohommed or Christ and the Church or Christ and anything.
Most importantly, I think there is a real danger in the 'legalistic' thinking of our construct-defenders that any human agency is capable of placing definitiional requirements on the nature and quantum of faith in Christ which is required for salvation. It is almost a matter that those who ask such a question are striving so hard to achieve the "bare minimum" (or in the case of our friends, striving to set hurdles so that they can contend that only their little group qualifies) that they do seek to place an improper condition on saving faith.
Now as to the second question: why do so few (relatively) appear to Christ? First, there is a caution that God tells us in Romans 1 ("For since the creation of the world God's invisible qualities--his eternal power and divine nature--have been clearly seen, being understood from what has been made, so that men are without excuse")that those to whom the Gospel of Christ is not presented will be judged on a different basis -- and we don't know much about what that is. Nonetheless, we know that repentance and unreserved trust in the Person of Jesus Christ is not without cost in this world. I am not sure we will ever know why this world and its various competing 'attractions' and philosphies should be so attractive to some. I personally believe that the function of pre-venient ("going before") grace is to so completely balance the decision-making scales that only the very slightest "weight" of our will tips the scales -- because God desires our voluntary love and acceptance of His gift of Life in Christ. So I personally believe that the relative numbers of people choosing to follow Christ (assuming arguendo that we have any idea what they are) reflect precisely the decisions of the will of the people confronted by His claims.
Finally, I think that the most important thing we can do for the people of the world in which we live is precisely the opposite of what our friends, the construct-defenders, do in these threads, i.e. present the attrtactiveness of the Person of Jesus Christ and avoid these pompous discussions of theological devices (truly, "constructs" manufactured by men) which only drive men from Him. The only reason I come out to participate is because the Calvinist construct presents the very grave danger of dissuading the unknowing from investigating Christ because they might believe the fatalistic nonsense the construct pedals, i.e. that nothing we do with Christ makes any difference. It is not only heretical but potentially fatal heresy as well.
As you well know and so often and carefully explain here, what we do with the Person of Christ is of paramount importance and the double predestination foolishness of the construct runs the risk of being truly a self-fulfilling prophecy.