The more voices singing this, the better. Loud is good. A bit of separation between the three words "We...are...American" is a good way to punctuate the sentiment.
If you are using the Performance/Accompaniment Cassette, you will be able to point out the recurring piccolo solo for your students. If you're not using the cassette, consider finding a good piccolo player to play it for your performance. Another option would be to let some of your more able-puckered students whistle the part. It's do-able. (When we recorded the cassette, the kids we used were singing the piccolo part every time, even though they had never heard the piccolo play it. We didn't record the piccolo player till the next day!)
You can also discuss the fact that while there is a basic rock pattern going on in the rhythm section (bass, guitar, drums and piano), there is also a snare drum playing a marching rhythm at the same time. This combination of styles is fun and unique, and your students will enjoy it thoroughly. The urge to move will overcome them.
If you would like to add movement, simple left-right shoulder movement during the lyrics would be easy to add, not to mention natural. While the piccolo solos are going on, you can even have them march in place, waving their flags to the beat. Practice which foot will start on which beat for uniformity. And here's a real Show Biz idea: Bring on the well-known "revolutionary trio" (The Spirit of '76) in costume, complete with 3 cornered hats and bandages, to "play" piccolo (fife) and drums. (See the "Freedom" poster in this issue for an idea.) They could either pretend to play along with the cassette, or you could have real performers. Again, those whistlers could come in handy here.
In the middle of the song, all accompaniment drops out except for the rock drum beat while the singers break into an a cappella round. The round is simple, repetitive and easy to learn, so singing with gusto shouldn't be a problem. Let your kids hear the performance version of this on the tape if you have it for an idea of how it will all fall together. If you are not using the tape, it is very, very important that a steady beat be established to keep everything together. Clapping on beat 2 (remember, it's in cut time!) is one way to help. (They'll have to tuck their flags under their arms for the time.) Another way would be to add your own rhythm instruments to punctuate the steady beat. A large cowbell beating two loud, solid beats per measure is probably the best thing to use. Remember that when the round comes to an end, the music needs to diminuendo back down to the piccolo solo. The word "Choices!" at the very end should be sung (or spoken) with enthusiasm.