Chests => nope, lockpick doesn't work, should've been 3 chests - in one large room? Or the small rooms? => There were 2 keys (picture/under pillow) And one there is locked and remains locked.
Nope, the guy is safe, until larians fix lockpick
Ringing => oh, the guards, who were in the room would just split up, so you wouldn't have to fight all at once. Just clicking on the gong would've set a cut scene - but I guess, your soldiers are ghosts now, right?
Maze => if you killed Laurel => no chance
Crowbar/keys => no use in Act 2