I'll try to answer the questions I posed in the order that I presented them, but knowing me, my comments will probably refer to more than one question...

I suppose that I don't need to add a disclaimer that the views I presented here are just my own and are arrived at in a very unscientific manner. Oh, I need such a disclaimer? Okay, then consider that last sentence my disclaimer :o).

1. There seemed to me to be differences in how the HBCU and non-HBCU marching bands entered the performance area. This relates to question numbers 15 & 16 since how the band entered the performance area helped build up {or lessened the audience's expectations} about what type of show they were going to experience from the band
If the audience expected a band to be "hot", then if the band marched in silently or just to the accompaniment of a solo drummer playing a beat with his drum sticks, that audience's expectations would be let down. My sense is that predominately African American audiences {and some non-African American audiences, I believe} want the band to immediately demonstrate that they are
"pumped up" to perform. When the band high steps in to a performance area to the accompaniment of a number of hot drum beats, and also when the band leans to the side {as I saw a drill team do, in the battle of the band program I attended Friday night, and have seen at other times, but come to think of it, maybe this is only done by drill teams}, the audience gets "geeked" {excited, pumped up, energized} and the audience shows it by their actions and their vocalizations-and that I believe is a key difference between predominately Black and predominately White aesthetic prefereces with regard to marching band {and drill team} performances.

2. It seems to me that the predominately Black bands played more music from R&B, hip-hop, pop music. These tunes were usually contemporary {meaning the latest hit song} but they might also be a golden oldie {a popular "old school" song}. The predominately Black band might also play music from Black religious traditions such as a familiar gospel song or a Dixieland jazz song. Perhaps the predominately White bands also chose songs that were from their traditions-it seemed to me that they were usually classical concert type songs or more classical jazz songs

{Note: In the case of the Madison Scouts, a number of viewers of their YouTube videos mentioned that this group used to be known for playing arrangements of Latin or Jazz tunes...Perhaps that is why they were my favorite Drum & Bugle corp groups when I used to watch the televised national marching band competitions in the 1980s}.

As appears to be the case in other stage performing arts, it seems to me that predominately White audiences don't usually respond spontaneously, or as often, or in the same ways as Black audiences perform. This goes allll the way back to African traditions about the relative lack of separation between audience and performer, and how people are expected to express by word and by actions how they are receiving the performance...

3. It seemed to me that the predominately White bands and the predominately non-White bands used basically the same kind of instrumentation, but I'm not sure since-again-I'm not a musician. It did seem to me that the predominately Black marching bands used the whistle as an instrument and I can't remember if the predominately White band did also...I've read and heard {recordings/videos] that the whistle was also incorporated early on [19th century?] into traditional African musical performances.

Also, I just thought of a question that could have been added- Did the band members incorporate vocalizations or chants into their performance-not just when they are marching in parades, but also when they are performing during half time? I think this is a difference between predominately Black and predominately White marching bands-meaning the predominately Black bands appear to do this much more often than the predominately White bands...I believe that this is part of the White aesthetic preference for pure sounds and the Black aesthetic preference for noisy,multi-layed, dense sounds {which in this context might be the same as "dirty" sounds but might not} See brief comments about African/ African Diaspora preferences for dense, mult-layered sounds in this article: http://northbysouth.kenyon.edu/1998/music/rhythm/rhythm.htm

Here's an excerpt from that article:

"African music values dense, noisy sound textures, also known as the timbre... Noisy timbres and complex, interweaving parts give the music a dense, rich quality.

This affinity for noisy timbres and dense sounds fit well with the cheap brass instruments available in the late 19th and early 20th century. Lieutenant James Europe's "Marching Hell-Fighters" band exemplifies this sound.

Listen to the Marching Hellfighters {click on link provided to get to this sound clip}"