Sorry I didn't get to this sooner, but I didn't expect to find such an inquiry here, and don't get here to check for posts that need to be approved often enough.
I think that we are only
assured that Seth was in Adam's image, because Cain obviously was not. In spite of the text at Genesis 4:1, Cain was not Adam's genetic son, although since Adam accepted Eve, Cain would have been his
legal son, as was later the case with Joseph the husband of Mary and Yahshua Christ. Genesis 4:1 is a corrupt verse, and there is evidence to show that. Nowhere else is Cain called a son of Adam, and there is much other Biblical evidence that he is not. There are papers on Christogenea explaining this, such as
Shemitic Idioms and Genesis Chapter Three and
The Problem With Genesis 4:1, among others.
Elsewhere we are told that the blood of Abel was "righteous", at Matthew 23:35 and Hebrews 11:4. Yet of Cain we are told that he was "of that wicked one", which must be an inference to the serpent of Genesis 3. So it is evident that there was no problem with Abel, but only with Cain. With Seth we have an assurance, or certainly we wouldn't even be here today!
Hope this helps!
Bill