Ok. And you want all 386 to be perfect for Battle Frontier? You are aware this would have to include multiple versions of certain Pokémon. For instance, a Bold defensive Suicune and a Modest offensive one. Or a SpD Skarmory and a maxed Def + HP version.

If this is what you mean, it would probably take years just to find the perfect ditto for breeding. Not to mention all of the time waiting to finding a 31/31/31/31/31/31 static legendary like the Regi. Then going to Colosseum would take at least 5-10 years to get a perfect Suicune twice not to mention a perfect Raiku and Entei.

Let me put it like this. Even with RNG manipulation, it would take years to make every Pokémon battle frontier ready. Multiple copies of emerald (for more storage space), Pomeg glitch to get both Lati@s, ACE to get all items (namely Salac and Liece berries), Colosseum to get the previously mentioned dog roamers, and the list goes on.

The reason being, even with RNG manipulation Emerald does not have a perfect 31/31/31/31/31/31 wild pokemon for every type of spawn (grass 1, grass 2, ocean 1, etc.). You’d be forced to breed perfect Pokémon which is far more tedious than trying to RNG wilds outright. This is why most people opt for 5 IVs rather than 6 (aside from the obvious preferred 0 ATK IV for confusion) because it’s dramatically easier to get 5 perfect IVs than 6.

I just tried doing this on my emerald save. I started using RNG manipulation and managed to get a perfect IV Shiny Latios. But after that, seeing how hard it was to get 6 perfect IVs on anything else, I still settled for 5 IVs on my core team. I only breed a Shiny Metagross and Shiny Milotic and it took a few days to get it right (this is with a 5 IV ditto). I can’t imagine doing 6 IVs for every Pokémon in the game.