That is correct.
Jambo, mind telling us how you loaded the pokemon in the 2nd slot?
I mean, you surelly know that the first slot is in 202402c and the second in 202402c + 0x64.
The way i load into there is manually, using data from another pokemon of another battle, saving his data into a file and then loading it to the offset when battle is about to start.
Did you used a routine or manually loaded the data?
I made the routine repeat the generation if the battle type was wild double. It currently generates a wild Pikachu (always) because of how I had to design it for now. But it shouldn't be outwith reach to have the game generate 2 random wild Pokémon.