When you say "SFX", are you referring for example to the wind noise, in this? https://www.youtube.com/watch?v=FVUVFcbaXMQ
If so, then good idea, at least for me, as I might use some to make BRSTMs with. This is <b>the</b> main reason why some of the music from BK and DK64 haven't been looped :P
Shouldn't be too hard to arrange the ripped midis with the soundfonts to sound like they should...just takes time and patience :P I think someone here is currently working on SM64 in that department for a remastered OST as well.