The anime is complete so if you want spoilers you can watch it
The model/idol is the Goddess' other half and Eve is who he falls in love with
No, Eve is human. It’s the same Eve from the beginning, the first human with Adam.
The guy is the goddesses other half, and the guy was supposed to be with the goddess I think- but he fell for Eve and I’m guessing he tried to seperate Adam and Eve and that’s why the memory flashback was of someone dying, which I assume is Adam, whenever Finne had flashbacks.
If i remember correctly there's this model/idol guy that was looking for eve right? Maybe eve is the goddess