There's some good stuff here but there's also some stuff to be touched up.
1. What type of skill level are you intending for this piece. Most band scores include 2 or clarinet parts, bass clarinets, baritone saxes, 2 or 3 trumpet parts, 2 to 4 horn parts, and 2 to 3 trombone parts. Now pieces for younger groups usually don't split the parts as much as the upper level things. If it's a lower level ensemble then I would look at some things in the range of the horn and trumpet.
2. Do you really want a baritone or do you want a euphonium? Unless you want baritone for some sort of solo passage you need to go with euphonium. No one plays baritones (except for marching band maybe). Switch it unless you actually want the baritone sound and you know the ensemble you intend it for actually has baritones. Nothing is more annoying for a euphonium player than getting a new piece of music that has a baritone part when they really mean euphonium. They are not the same thing.
3. I'm assuming you mean orchestra bells on bells part. I'm pretty positive they can do trills but probably not as excessively as you'd want. Also the have a decay that you have to watch out for. Be aware that passages with a lot of notes will blur. If you don't want that sound than switch to another mallet instrument.
4. Generally you group four four bars into one beat groupings, rather than the two beat grouping you have. Also connecting eighth notes over rests is confusing to the performer.
5. Besides all of the above clean up your score some.