Huh ? I can't see anything like that. As I see, Name Tables contains only "standard" data (no characters are unvisibles beacause of Chr-Rom or anything like that.
But I did check only the English version, I'll do this for the japaneese one to understand it.
Note that one of the 3 battle's music uses DPCM, so it can't be used in (some) battles.

->Rad Racer 2 also does the $4011 drum popping sound (definitely only one or 2 writes per frame, because that game is very timing-dependant).
Yeah, it does, and SD Gundam 3&4 does both, too.
Is it possible to have a same effect with the MMC5's $5011 easyly ?

Bregalad, Ent from the woods of Fangorn