2 is the poisoned pawn, 13 is the grob, 12 is the fried liver...
Fifteen pieces and a mate

There are twenty openings and only fifteen pieces, so I guess five aren't used.
Yes

8 is the pirc, 15 is the dragon, 14 is trompowsky
8 & 14 correct, 15 is not the Dragon
In the position below, every piece's position is characteristic of an opening from the list below. Can you match the "representative" pieces with the openings?
Bonus: If it is white's turn to move, how many moves to mate?
Pirc Defence - 8
Sicilian Najdorf, Poisoned Pawn - 2
Larsen's Opening
Two Knights' Defence, Wilkes-Barre Variation - 11
Trompowsky Attack - 14
Saragossa Opening - 5
Sicilian Dragon - 6
Alapin's Opening - 9
Sicilian Najdorf - 1
French Defence - 10
Reti Opening
King's Indian Defence, Bayonet Attack - 3
Benko Gambit - 4
Vienna Game
Center Game - 7
Grob Attack - 13
Two Knights Defence, Fried Liver Attack - 12
Caro-Kann, Main Line - 15
Alekhine's Defence
Robatsch Defence
Bonus: Five moves to mate, beginning with 1.Qf6+ . Congratulations to Rooperi!