Is believing in God for salvation the same as believing in Jesus as Christ?

I'm interested in answers particularly from Evangelicals who might disagree with this idea, as well as those who agree with it. I'm especially interested in theological considerations — i.e. does this misunderstand the Trinity. Essentially the thought came to me, **if the Son is fully God, do those who have *never heard*** the Jewish name of the Messiah (Joshua, meaning the Lord saves) or the exact details of his virgin birth, death, and resurrection, **nevertheless believe in him** (for salvation) **when they trust in 'God' to forgive/save them?** This excludes those who reject Christ explicitly (ie. orthodox Islam). This would not be a universalist position, but a form of inclusivism. More like a psychological/conceptual faith in the Messiah/Christ/Savior. I'm looking for arguments for/against, as well as relevant verses/examples/doctrines. A similar question was asked here , but this gives it a trinitarian/soteriological bent. For a practical consideration, Don Richardson (*Eternity in their Hearts*) notes a number of peoples geographically and intellectually isolated from Christianity/Judaism for centuries that had an underlying monotheism, and belief that this 'creator' was going to set things right if they only waited for special messengers bringing a special 'book'. Would their 'waiting for salvation' be comparable to some in Israel during the intertestamental period, waiting for the Messiah?