Your contention that the apostles and early evangelists did not preach hell or appeal to the self-interest of potential converts has led me to search the Book of Acts and compile a list of the theme of their preaching. I was struck by how briefly Luke describes what was preached. Often he says no more than that they "preached the gospel", "preached the Lord Jesus", "preached the kingdom", etc.
I found the following themes emphasized, with my count following:
1. Jesus as Christ, Jesus as Savior, Son of God, preached Jesus - 14x
2. Resurrection - of Jesus, of righteous and wicked, general resurrection - 9x
3. Gospel, good news of kingdom, Kingdom of God - 7x
4. Repent, repentance - 6x
5. Sins wiped out, sins washed away, forgiven, forgiven through Jesus - 5x
6. Believe in Him, believe in Lord Jesus - 4x
7. Crucifion of Jesus - 3x
8. Salvation, be saved - 2x
9. Turn from vain things, righteousness, self control - 2x
10. World to be judged, judgement to come. - 2x
11. Baptism - 1x
12. The word of God - 1x
13. Inheritance. - 1x
14. Sanctified by faith. - 1x
15. Turn to God. - 1x
16. Perform deeds appropriate to repentamce. - 1x
17. Proclaim light to Jews and Gentiles. - 1x
I found it interesting to note that much of what they preached must have been unrecorded by Luke. For example, Luke's telling of the story of the encounter of Philip with the Ethiopian eunuch makes no mention of Philip instructing the Eunuch regarding baptism, but we know there is a high probabability Philip did because the Eunuch asked to be baptized. Likewise all through Acts we find people being baptized with very little mention of baptism being preached.
To my mind the preaching of the need for sins to be forgiven and the judgement to come strongly implies the preaching of the consequences if they failed to repent. And what might those consequences have been? I think hell is a good candidate.
It is not a strong argument you have about hell not being mentioned by Luke; it is difficult to prove it because of Luke not mentioning it, especially in light of his extremely brief description of the content of their sermons. It does seem to be implied, while there is no mention or even a hint that anyone was instructed that they must deny self, bear their cross, leave or forsake everything, die to self, etc. We can not prove that nothing was said about these things, but it is curious that Luke never mentions these ideas.
It is interesting that when Jesus appeared to Paul he instructed Him simply to:
As always, I will be interested in your comments."...open their eyes so that they may turn from darkness to light and from the dominion of Satan to God, in order that they may receive forgiveness of sins and an inheritance among those who have been sanctified by faith in Me."
God bless, Homer