Yes, I think Dragonite will probably be the one to beat Rillaboom and then gets taken down by Charizard. So she will be facing Dragapult Rillaboom and Charizard to compensate for that poor Cynthia showing.
Sirfetch’d is definitely winning against Mr Rime and I could see Dracovish beating Dragapult.
My ideal battle would be:
Mr Rime vs Sirfetch’d (w)
Dragapult (w) vs Lucario
Dragapult vs Dragonite
Dragapult vs Dracovish (w)
Cinderace (w) vs Dracovish
Rillaboom (w) vs Sirfetch’d
Rillaboom vs Dragonite (w)
Cinderace vs Dragonite or Pikachu (w)
Charizard (w) vs Dragonite
Charizard vs Pikachu
Honesty I doubt that they would have Mega Lucario lose yo Dragapult especially when it only has one attack that can do damage to Dragapult.
It’s much more likely that what will happen is after Mega Lucario lands a Bullet Punch or a few of them on Dragapult that Dragapult’s ability Cursed Body activates disabling Mega Lucario’s Bullet Punch, which causes Ash to decide to withdraw it.
So where probably more likely looking at the battles going like this:
Mr.Rime vs Sirfetch’d: Sirfetch’d and recalled
Dragapult vs Lucario- - -> Mega Lucario: Mega Lucario is recalled
Dragapult vs Dragonite: Dragonite is recalled
Dragapult vs Dracovish: Dracovish
Rillaboom vs Dragonite: Dragonite
Cinderace vs Mega Lucario: Mega Lucario
Charizard vs Pikachu
So basically each of Ash’s Pokémon will get a win but will take damage in the process. Also I’m unsure of the order Rillaboom and Cinderace will come out in.
Now presumably they would want to Rillaboom and Cinderace to both get a win which would probably be them taking out Sirfetch’d and Dracovish respectively.
However there is the possibility that we could get a situation similar to what happened in Ash’s full battle against Drake in the Orange Islands where Ash initially only lost two Pokémon but the rest of his team had taken damage in the previous battles and his remaining team members took on Drake’s Dragonite.
So basically Ash could wind up still having 4 or 5 members left by the time Leon is down to his last Pokémon and that it winds up being Ash’s 4 or 5 remaining Pokémon against Leon’s Charizard and with Charizard taking out 3 or 4 of Ash’s remaining Pokémon in the 3rd part of the battle.
The 4th and final part of the battle focuses on just the battle between Charizard and Pikachu and maybe one other Pokémon on Ash’s side if he still has one besides Pikachu that isn’t knocked out at that point.