1, Madara Uchiha, Nagato, Obito Uchiha and The Sage of Six Paths ( Hagoromo). Total of 4 ninja can summon Gedo

2, Kakashi destroyed the first heart with his Lightning Blade, the second was destroyed by Hidan by accident (Shikamaru trick), and Naruto destroyed the remaining hearts with one Rasenshuriken, but it was Kakashi who delivered the killing * just to be safe.

1.Kakashi2.Shikamaru ( using Hidan )3.Naruto4.Naruto5.Kakashi

Note: In the past some number of hearts were destroyed by Hashirama and in 4th GNW by TenTen . So if we say all five KONOHA ninjas with no duplicates it should be :

Hashirama,Kakashi,Shikamaru,Naruto,TenTen

3, two pots with 3 flowers each = 6 flowers