I also was confused but I'm assuming since the kept on saying they had grew up strong enough to make their own path they would be going back and I dont think they would need to be a god or anything to go back since her friends could see the yokais and things as long as they were in the shrine
Well, the incest was unintentional. The Guy didn't know and neither did she until pregnancy. I think people mean her relationship with frogman was cute. They both grew a lot with each other and they make each other better. They slowly falling in love was really cute.
I kind of wish there was a time skip and we saw Rui all grown up and cool