BrodiemanTTR said:
That's not entirely true. The majority of composers were brought on because Sakurai wanted to gather the most talented composers in all the land to contribute to the game, that's the reason for such an impressive list of non-Nintendo developers. However, any third-party characters will need to have the composers from their respective franchises brought on board to score their stage/theme/etc., so that huge list is related in a small way to third-party characters being in the game, it's just near impossible to deduce with such little information.
not true at all,
who is to say the music from, say Metal Gear solid, will even be an arrangement by Akihiro Honda. Perhaps Totaka is doing the MGS music stage????
The list is just a list of the folks arranging the compositions, not of the original composers. My guess is that Sakurai put out a call for any talented composers with a desire to arrange Nintendo music. The people who responded are either his friends, folks who appreciate certain N soundtracks and have had a desire to work with the music, or both. Did you know Takada was a fan of Totaka's music? Neither did I, but clearly he is. Sakurai probably got the group together and then asked which Nintendo (or others) songs they'd like to try. It gives a fresh take on every song.
They may have kept all 3rd party song mixes in house, just to keep the roster from leaking. Also, there may be some Nintendo composers who are big fans of the stuff in MGS, Mega Man, Sonic... who want the same opportunity to mix songs that have inspired them.