Hello Timothy.
A few questions/comments. (questions are meant to engage you in discussing what you did, and thinking about the reasons you chose that route. Comments can then address whether your choices were the most effective.)
1st chord:
why did you reverse the order of the 1st and 2nd trumpets?
in the chord, you left the 5th of the chord (A) to a single instrumental group - 2nd violins, in a very medium range. this will weaken the sound of the 5th considerably.
I notice that there are no trombones.
Also the range of the viola is rather on the low side.
If by "bold/military" we are understanding the same thing, I'd rather have suggesting emphasizing the tonic and 5th, for example, your 2nd violins could be playing A and D, open strings. The 1st violins could also be playing a double stop, that higher D and the one an octave lower (unison with 2nd violins, open string D). The cellos could be doing the exact same thing as the 2nd violins, one octave down (again, on open strings).
My suggestion is "think like a bagpipe". military? the drone of the open strings would emphasize that.
2nd chord:
Think of the mood you are trying to set... "melancholy". Would you think in terms of bright and colourful, when thinking "melancholy"?
You have a pair of flutes in a very bright, clear register.
You have a major no-no in the oboes... the joke about "how do you get two oboes to play in unison?" doesn't actually exist in a vacuum. It is VERY difficult to get a clean unison from two oboes.
The clarinets aren't in a bad register, but it might have been nice to take advantage of the richer lower octave, the chalumeau register, where the sound is dark and rich.
The two bassoons are in a somewhat "bright" register. Maybe consider lowering that a tiny bit. You don't have to bring both bassoons into a deep low register. you could have one play a bass note, and the place other between the two clarinets (if you lower your clarinets).
The harp is, by its very nature, a bright sound. Remember that the string is pinched, giving it a "ringing" tone. Why not use the harp as a very low note? how about the root of the chord, in octaves, in the harp's lowest register? The longer string length at that point tends to tone down the brightness and gives a richer, darker sound.
For the strings.... you might even leave out the violins completely. USE the string section to its best advantage.
The violas have a naturally dark tone. Combined with the celli and contrabass, there is potential for a very rich dark sound there.
If you do include the 1st and/or 2nd violins, consider giving them low notes, something that mitigates the natural brightness of the violin.
Of the strings, the violin has the shortest and tightest strings (the tension on the strings is highest on that instrument). This affects the tone.
3rd chord
I'd suggest reversing the effect here. have the brass play heavily accented, while the rest of the ensemble just plays a short note.
For anger/shock, I'd suggest placing the string pizzicato in a higher register. The higher a pizz is, the tighter and more percussive it becomes. The lower it is, the more resonant it is.
A consideration: have the contrabass and celli play a Bartók pizz. For mazimum effect, the celli would have to be one or two octaves lower.
4th chord
For a "happy" chord, is darkness in timbre the desired effect?
Examine the registers you've chosen for your woodwinds.
Just a quick note in the strings: the pizzicato, whether indicated as a quarter note or as a half note, will have the exact same resonance. It's a short percussive sound.
With more experience, you could (particularly since this is a D major chord... a ridiculously easy chord to play for a string player) have almost the entire string section play triple stops (3-note chords in each instrument).
All in all an excellent first attempt.
You'll find, as you become more comfortable with instrumental possibilities, you become more and more adept at creating types of colour and mood.
