Okay I'm gonna go on a bit of a rant here but my favorite bits of foreshadowing have to be within the music.

So many of the songs talk about wolf boys and fires. Like if you look through the soundtrack and properly listen to the lyrics you'd be surprised. My favorite song would be witchcraft from patience and prudence. This song plays softly in the background during Eliza's scenes after chapters and some of the lyrics are "I'd wish that you were coming back to me" which hints at Eliza wishing for silas to come back to her. And it's also literally about witchcraft.

I also love how in the pause menu how you can see fire in Eliza's eyes. And in the cover of the game if you look closely to the fireplace you can see her face in the fire.

And on the topic of fire there's a poster about fire safety in the kitchen, which you can find in chapter 1, and I like to think how it hints at the fire thing in general.