OK, so, as it turns out I have Type 1 midi files in BIAB set as the default. I also did not know the difference between type 1 and type 0 midi files. So, now I do. lol

I was just confused why when I dropped the midi into Reaper, it became multi track. It made no sense to me that I would need multiple copies of the same VST to play the performance of one instrument. (But, apparently, the best use of MIDI type 1 would be for drums.)