Shiny Rates for Legends: Z-A Mega Dimension DLC Determined

Thanks to Anubis (@Sibuna_Switch), we now know how shinies work in the Mega Dimension DLC! With the DLC, Sparkling Power makes a return though with a few modifications and 5 specific Legendaries can be shiny.

First and foremost, please be sure to check out Anubis' thread and leave her a thanks for all of her hard work. We wouldn't have definitive evidence of these mechanics without all of her hard work. Here's her thread detailing the findings, which I'll reiterate here (and put in our Shiny Rates page for the game).

Wild Encounters and Sparkling Power

To start off, the base shiny rates are unchanged, without any bonuses the base rate 1/4096. The shiny charm still rewards an additional 3 shiny rolls (for a total of four) giving you a new rate of 1/1024.38.

Sparkling Power gives an additional roll for each level you have, so Level 1 gives 1, Level 2 gives 2, and Level 3 gives 3. This bonus only applies to Pokémon that share a type with the Sparkling Power the donut provides. Here's a copy-able version of Anubis' table:

Sparkling Power Level 3 Guarantees a Shiny

When you enter a Hyperspace Wild Zone with any type of Sparkling Power Lv. 3, the game forces the first Pokémon that spawns in that also matches the Sparkling Power type to be shiny. Note though that this forced shiny will only happen in the group of Pokémon that have spawned close to the player.

There is also the "Catch Shiny Pokémon Task," which appears when the player first arrives to the distortion if any of the initial Pokémon are shiny (it doesn't matter if it was because of Sparkling Power Lv. 3 guaranteed shinies, a "full-odds" shiny or any other shiny).

The guaranteed shiny does not affect any other shiny rolls or other Pokémon. There was a dumb rumor going around that this forced shiny would cause other Pokémon to lose shiny rolls, that rumor is entirely false. It is still best to get a Sparkling Power Level 3 bonus to maximize shiny rolls across the distortion.

Anubis made a great video demonstrating what is and isn't affected by Shiny Charm and Sparkling Power, please be sure to watch it.

Shiny Locks

The same locks from the base game still apply. The special spawns of Latias, Latios, Cobalion, Terrakion, and Virizion are not shiny locked, you can hunt them to your heart's content! All other Legendaries/Mythicals, Rogue Megas, scripted battle encounters, Pokemon part of a mission, NPC gifts (excluding fossils), and in-game trades are all locked.