I find it very attractive with the blue jacket, and it does have historical resonance. Its very similar in effect to the uniforms of the 19th-early 20th centuries.
They would look snappier with closed collars in the true 19th century style.
The berets are a poor match with the uniform I think, as are the womens hats. A stiff Kepi would be better, or a Stetson-type campaign hat, though that is much less practical.
I understand the significance of blue — Civil War esp, but the apex of the US military’s worldwide respect was (remains) WWII.
The WWII/Korea uniforms look like the “Army” to me — perhaps because of movies (and they didn’t change all THAT much circa 1986-96 — my time).
If they had to go different, maybe WWII style in kahki.
I think a Mississippi Marine Brigade/Ram Fleet "dragoon" style hat would work, too.
Mr. niteowl77