I think the fact that the family's "fasal" went on fire, I felt that was forshadowing that the family will be destroyed in some way. Then the fact that Teji sold the chain to pay for the guys who were going to make Heer's Mandap, I felt it was forshadowing their death, because when Balraj finds out, he says "you have gotten rid of our only "Pyaar Ki Nishaani"".
I think that Manmeet has caused this "accident". Because when you see his face when Balraj and Teji leave Daljeet's house, his face is like he's going to take revenge!
Just my two cents...