Kyogre
I got 4 Kyogre with 88iv but they all have different stats:
Hp Att Def
15 15 10
13 15 12
12 15 13
10 15 15
Which will be the best one?
Answers
Funny enough, that I have the identical Kyogres as you as my best ones, except for a 15Hp14Atk13def one, which I powered up to L31.
As I like having two Kyogres ready I will go with the 15HP-15Atk-10Def one. Why? Kyogres base stat lack HP; so I focus on that the most. In combination with the lower Def it will MAYBE gain energy faster in some situations, as it takes more damage. Those 5 HP extra should make up for that extra damage though. Aside, there are very few bulkpoints, not sure if any, where the def stat made a difference in damage taken in my simulations, usually the one with more HP at the beginning had more HP at the end too. Kyogres base Def is already pretty high; so the slight boost it gains from 5 Def wont matter much anyway.
Edit: I agree with the answer above me though, my sims backed up, that there is barely a performance difference between them, any Kyogre with 15 Atk is a good Kyogre.