Chicago Riddle Co. Mystery Cache

This cache has been blown away from the posted coordinates.  Some of the riddles below will blow you off course, but one will put the wind in your sails and bring you to port.

• What is the next 3 letters in this riddle? o t t f f s s _ _ _
• Marking mortal privation, when firmly in place. An enduring summation, inscribed in my face. What am I?
• This thing all things devours/Birds, beasts, trees, flowers/Gnaws iron, bites steel/Grinds hard stones to meal/Slays king, ruins town/And beats high mountain down.
• I was named for my garlic. Mrs. O'Leary's cow burned me down; Scarface brought out Tommies for Valentine's Day; a famous dance in me is the "Cell Block Tango".  Where am I?
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  You can validate your puzzle solution with certitude.