Agreed. No one in the OT warned about it as a consequence of sin, God didn't use it to warn Adam and Eve, and Paul never did (who said he preached the WHOLE gospel). I think it's impossible that ET could be an option if not ever warned about throughout the whole OT.
I completely agree. However, some Mainstream Christians argue that Hell was created for the devil and his angels around the time when Lord Jesus was resurrected and it is the ultimate destination of all who don't accept Lord Jesus in this lifetime. Some of them also believe that Abraham's Bosom was the original Heaven before Lord Jesus came along while the original Hell was the grave/sheol. In other words, many believe Hell didn't exist in the OT but it appeared in the NT
Related to the above, I believe annihilation/total destruction makes more Biblical sense than eternal torment. One could easily glean that from the OT alone. However, since the NT is so full of the restoration/reconciliation of all/everything gathered together in Christ, then it all must reconcile.
Neither should there be vulgar speech, foolish talk, or coarse jesting--all of which are out of character--but rather thanksgiving. Eph. 5:4 ** Saved 1John 3.2, Eph. 2:8, John 1:12 - Being saved 2Cor. 4:16 2Peter 3:18 - Will be saved 1Peter 1:5 Romans 8:23