I'm not sure weather you are referring to the chords or the range of the tenors at G, but everything in here is easily in a tenor's range, especially a high school tenor.
Also, I don't know if this has been addressed yet, but although it might not be a traditiona marching band setup (I thought it was, but I guess I was mistaken), but a lot of marching bands have bari saxes. It would be better if you wrote them a line, especially because if a school has some bari's (which they should), they'd have to either write their own part from the tubas, or play the only other thing in Eb (alto).
Also, I do partially agree with the tenor sax unison thing. as a tenor saxophoneist myself, I find that tenors are best for harmonies and countermelodies. But that's just my opinion.