I rewatched the preview for this episode and I noticed that when it's Incineroar vs. Melmetal that on Ash's board, the order of pokemon goes: Melmetal, two blank spots (most likely Lycanroc and Rowlet), Pikachu, Naganadel's pokeball, and Torracat. This leads me to believe that whoever gets called out will go to the top spot while the pokemon it replaces will take its previous spot. So that means Torracat gets recalled for Pikachu and Pikachu gets recalled for Melmetal. So the flow of the battle might look more like this:
Braviary vs. Lycanroc (double KO) [order = Lycanroc, Torracat, 3 pokeballs, Pikachu]
Venusaur vs. Rowlet (Venusaur wins) [order = Rowlet, Torracat, blank Lycanroc, 2 pokeballs, Pikachu]
Venusaur vs. Torracat (Torracat wins and is recalled) [order = Torracat, blank Rowlet, blank Lycanroc, 2 pokeballs, Pikachu]
Empoleon vs. Pikachu [order = Pikachu, blank Rowlet, blank Lycanroc, 2 pokeballs, Torracat]
Incineroar vs. Melmetal [order = Melmetal, blank Rowlet, blank Lycanroc, Pikachu, Naganadel's pokeball, Torracat]
Kinda worried for Melmetal in terms of it getting a win unless Pikachu is recalled against Empoleon and Melmetal finishes it off. Because I do think Incineroar will be saved for Torracat. Hoping that article pointing out that Naganadel is a pokemon to look out for means that it can get a win at the very least.