I'm not sure if it's worth noting or not, but there seems to be a sprite glitch that keeps defeated Pokemon on screen after they've fallen in battle. I've only seen it happen with opponents PKMN and it seems to be random, but It seems like it should be reported. Also, there's another glitch that's rather annoying. Sometimes, when you become poisoned, after defeating a pokemon that would end the battle you take poison damage first. This shouldn't happen and can (in certain rare cases) cause you to lose the battle. It's VERY annoying and I hope that it can be fixed sometime soon.
Best Wishes
You should try using Vocaloid for this, it could work for you well...