I find this highly intriguing.
I'm still cutting my teeth on the conversion/compression process for SMK music. I've succeeded in replacing the first part of the Title Screen anthem, but my Choco Island replacement music somehow prevents the Pre-Race Fanfare (when the camera pans down the center of the racers, then spins 180º) from loading/executing properly. Then $[DF00-FEFF] region of SPC-RAM gets flooded with gibberish and everything dies.
Which trackform gets the theme from "Silence"?
One thing you might want to consider re: the F-Zero songs is rearranging their channel layout. During active Mario Kart races, certain sound effects are played on specific channels, which may cut off or even silence certain parts of the BG music. My research has yielded thus:
Channel 4: Coin Collection, Start/Select, Hopping, Item Use.
Channel 6: Most environmental SFX (water, sliding, skidding, offroad).
Channel 7: Other racers' engines.
Channel 8: Your engine.
I've come to take as read that, at least for songs intended to play during active racing, Channels 4, 6 and 8 are off-limits and Channel 7 is to be used sparingly.