Can't you give a straight answer to a straight question? Will all these people go to hell if they don't accept JC as their personal saviour?
Jews and Muslims worship God the Father, does that count or is JC the lynchpin?
All men who are cosmic rebels against their creator suffer his just punishment, so you tell me. It ain't hard logic.
Neither I, nor the scriptures are prepared to grant that premise. Romans teaches that men hate the true God to the point that the worship of false gods, rather than an attempt to FIND God, is rather an attempt to RUN FROM the true God, while satisfying their religious impulse.
You say they are innocently mistaken, and just doing the best they can. I will go so far as to say that if that is true (and it ain't) then NO, God would not be so unjust as to condemn a man simply for not believing in someone he never heard of. However, the biblican picture of man and his determination to subvert the knowledge of the true and living God is quite a different picture.