So I messed around with this a bit further and figured out a few things. I managed to edit together 2 midi tracks to make a custom HNIC theme from the 90s. I used MixPad and altered notes etc to sound similar to the track, then I went to work changing the notes to a single instrument. From there, I exported a midi track and ran it using smoz' python script.
Because there were multiple notes playing at the same time throughout the track (like chords), THAT is how you can cheat and have multiple instruments at once. The thing is, trying to separate them according to tone is super difficult. The EASY way to do it is to simply assign an instrument to a pitch range. It's not 100% foolproof but it's pretty good.
As you can see in the image above, any note played in the '40' range from column D was assigned channel 0 (90/80). Every pitch with values in the 50s got channel 1 (91/81) and so on and so forth. I ended up with 6 channels and used 3 instruments.
Channel 0 = 0B
Channel 1 = 08
Channel 2 = 04
Channel 3 = 0B
Channel 6 = 08
Channel 7 = 0B
I wanted more of a brassy sound because of the horns in the actual track and the 0B chorus synth worked fairly well, with 08 having some decent single sound reverb.
HNIC-2.mp4
If you notice, I figured out how to get the song to loop. At the end of the original NHL94 theme is a 10 byte footer(?) that I pasted at the end of the midi information I put in from smoz' script. It looks like this:
If you copy the highlighted part and slap it at the end of your track, it should loop, regardless of what comes after it.
We're getting there... the sound barrier has been breached LOL