Brian,

This is what one soldier had to say about uniforms.

(Quote) We went through the war without a uniform. We were lucky to keep our bottoms covered. When I got into the war, we wore overalls, and when we surrendered in 1865, I didn't even have a pair of shoes.
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The gold cap.....may be a kepi with a yellow or gold trim.
A yellow trim was for cavalry, blue for infantry, and red for artillery.

SHELL JACKET
You can get a shell jacket, that would work. Again here is what a soldier had to say about jackets.

(Quote) Here they were, then, the real truculent and unmitigated rebels, in butternut of every shade, from the dingy green to the tawny brown and faded tan ... butternut, mixed with a dull characterless gray. There was no uniformity, yet there was something common in the dress of the whole company, a faded look...

TROUSERS
Sky blue, gray or butternut trousers will work. Again a quote from a solder.

(Quote) Thousands were ragged as they could be ... some with the bottom of their trousers in long frazzles, others with the knees out. One had the seat of his trousers patched in bright red, and his knees patched in black...

Boots or Brogans

If you use boots they would be knee high low heel and square toe, or Brogans.

Again a soldier quote on footware....

We wore hide shoes, which were made up from the green hides of cattle, killed for food, sewed up with thongs or strips, the hair side being inside, next to the foot.

I hope this will give you an idea or two for your uniform,
Gary D. Bray