Also, Pyroar will actually be an excellent choice for Charolette because the rainbow field that will be created through the combination of rain and sun will give a nice extra 1.5 boost to his STAB Hyper Voice, which should hit both of her Pokemon. Strength would work too though. When you see one of her Pokes going for either Solar Beam or expect to take a fire move on your Bronzong or something, make sure to switch into Pyroar which will eat it up and be ready to start sweeping through her team. The Moral of the story is when you've got a nice, strong, Special Attacker that can outspeed a level 75 Arceus while at level 60, don't box it. Keep it trained up and ready for battle, esspecially since you can quite easily create the Rainbow Field while working with the weather. If it's sunny you can make it. If it's rainy you can make it. The Rainbow Field is an easily manipulated field that you would do well to utilize with Pyroar.
Also it really surprises me how many people forget about this tactic. I didn't even have Hyper Voice on my Pyroar, I had strength, and it killed four members of her team and then Archen and Flygon cleaned up.
Edit: It just came to my attention that you said you didn't have any more Heart Scales, so really the only choice you have for getting rain dance, which is essential, would be Castform through level up. Make sure you ALWAYS go back and get TMs like this in Reborn guys! You won't want to backtrack and grab TMs like Rain Dance, Sunny Day, Hail, and Flash.