I have long been skeptical of the category of "essential doctrine" used for determining precisely what a person must believe in order to be saved. The sheer variety of possible errors, their many possible degrees, and their countless conceivable motivations and sources make it almost impossible, in my opinion, to specify a few specific doctrines as those which are absolutely necessary for salvation. We can reasonably identify a few prerequisite doctrines without which there is no possibility of a Gospel at all (e.g. God exists, Jesus rose, etc.), but it's a much less plausible task to go beyond this to enumerate a set of essential doctrines which, if a man gets them wrong, he is certainly damned.
I was happy to find, then, that Herman Bavinck, the great Dutch Reformed theologian of the 20th century, seems to have agreed with me:
Although the distinction between essential and nonessential articles of faith was important for ecumenical relations between Protestant groups, it had the potential for reducing the faith to quantitative measurement. Such an arithmetic of belief obscured the qualitative, gracious, personal, organic relation to Christ so important in the Reformation protest against Roman Catholic sacramentalism and its doctrine of implicit faith…For the Reformers, faith is trust in the grace of God and not calculable; it is a personal relation to Christ and not subject to quantifiable addition. The content of faith is not reducible to an arithmetic addition of articles. Herman Bavinck, Reformed Dogmatics: Abridged in One Volume