Brothers and sisters:
May I say something and not be taken for a heritic. There are things the Bible is silent about, others the Bible is mysterious about..( meaning hinting to but not explaining in full) among these the passages in 1 pet that seem to be saying that christ preached the Gospel to dead people.
Yes, Christ is the only way to life, but there is so much that we do not know.
Will someone who had never heard of the name of Jesus, never read a Bible, but only knew from creation that there must be a God, will such one have the opportunity of having the Gospel preached to by Jesus even after death. We just don't know. There are things the Father has kept in His knowledge and we are not to be dogmatic about. Our job is to get to know God in such a close way that He may entrust us with His Holy Spirit and fill us that we may be able to tell every creature about Christ, and leave the rest to God.
1 pet 3:18 Because Christ also suffered for sins once, the righteous for the unrighteous, that he might bring us to God; being put to death in the flesh, but made alive in the spirit; 19in which also he went and preached unto the spirits in prison, 20that aforetime were disobedient, when the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls, were saved through water:
1 Pet 4: 6 For unto this end was the gospel preached even to the dead, that they might be judged indeed according to men in the flesh, but live according to God in the spirit.