The Selection Screens have had an update since they were last seen. This time, instead of having a giant list of them, the new space with the GBA has been utilized. Now you have your party on one side, and your lead Pokémon on the other. Here's the picture of it:

Selection Screens - In the Pokémon Part of Menu

However, things are different now the 2 on 2 battles have been introduced, a few changes have occured when you go to change pokémon. Firstly, If you get entered into a 2 on 2 battle, The Lead Pokémon and the top one of the list will go into battle, however when changing the Pokémon in battle you can change one Pokémon or both, or just switch their places (even though that doesnt make a difference, just wastes a turn) here's an example of that page:
Selection Screens - 2 on 2

 
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