[Urwen]

Well, in books it clearly states that Morwen (and Turin) suffered because Lalaith died. Hurin too. He tried to sing a song for his daughter, but failed and cursed Morgoth that Valar (and Turin) would finish him off

Meanwhille, Thingol had shady negotiations with Haleth & Nellas. He made a deal that if they killed him, he would have fun with them in Mandos. You really think dwarves killed him? No, it was Nellas and Haleth with her people, disguised as dwarves. Hurin, of course, participated, as dwarf named Ibanzil (which means 'leader').

Turgon disliked dwarves, and Maeglin disliked mortal men. Yet, they harboured Tuor, along with his little 'sister'. But his 'sister' was, in fact, his cousin. He of course, renamed Lalaith, for purpose of saving Idril. He renamed her after Idril's mother.

Hurin, after killing Thingol, and after Melian left, Hurin threw himself in the sea.

As for Lalaith, she personally threw Maeglin off the cliff. People confused her with Tuor because they're cousins. Real Tuor, along with Idril and many others, already escaped. After washing her hands, Lalaith went after them and joined them at havens of Sirion.

And everybody (except Hurin and Maeglin) lived happily.