Oh, so you're still alive LOL
I haven't forgot that you kinda forgot the problems you had with some of my tools, ya know?
As for your question, scripting can't do anything, because all you do is starting the trainer battle, and you can't really choose the music that's played. Now, if you want to change the one that's played right -before- the battle, you can simply use A-Trainer. Be aware however it's bound to the trainer class the trainer belongs. Anything else requires ASM.