How can I be sure to open every chest in the Omega Ruins?

What is the minimum my Luck stat can be in order to guarantee that I hit Dark Mindy every time?

If I decide to stat max on the Expert Sphere Grid, including HP, but forego Evasion and Accuracy due to maxing out Luck, about how much HP will I end up having?

If I am fighting a Shred what is the percentage that it will use its 'Slam' attack and what is the percentage that it will use its 'Slam' attack against the character with the lowest remaining HP? What if Auron is in the party?

:rolleyes2