If they win on the Warrant in Detinue, they can have the sheriff come to your abode to pick up the items. Seems like not much will happen since they have an old address and you don't have the stuff anymore, but who knows? When they said they didn't want the stuff, did they put in writing? I'd answer the warrant in detinue with a copy of your duscharge and a copy of the letter, but, I'd show up, just in case. If things go haywire you should talk to a lawyer about them violating the discharge.
Unless they go back into bankruptcy court seeking relief, you shouldn’t have any worries. Likely the worst thing that happens is you could have to pay the fair market value of the property if you can’t return it.