salvation of non-Christians

Is Jesus the only way to heaven?

Yes--"No man cometh unto the Father except by Me."

No--"The Father is not willing that any should perish."

If Jesus is the only way to heaven, can salvation be somehow extended to non-Christians?

Yes.

No.

Could someone who never heard of Jesus Christ still be saved if he was open to God, sincere, honest, and followed his conscience, provided it was ultimately only by Jesus Christ that he was saved, though he wouldn't know it until he reached heaven?

Yes.

No.