Ostrich feather plumes are considered by many as de rigeur for the Civil War outfit. Alas it is very much a Victorian fancy dress construct, and generalisation based upon portraiture of the great and good.
The Wars of the Three Kingdoms became very fashionable thanks to Walter Scott's treatment of Montrose. Queen Victoria was appalled by Montrose's memorial stone in Edinburgh and ordered the statuesque memorial that we see today. The romantic ideal became a cause celebre, and the dashing cavalier/crop headed Roundhead imagery became cemented in the nation's consciousness.
Being a cavalier at grand fancy dress balls and pageants became the height of fashion. Surviving clothes were not in keeping with this Victorian ideal so were modified (!).
Alas these wrong but wromantic/ right but repulsive images live on in film, pictures, and figure ranges.
Historical evidence and Occam's Razor tell us that big plumes would be few and far between.
Ostrich feathers were ridiculously expensive bling that appeared in portraits of the very well to do. The fashion for blingy feathers adorning hats trickled down to the masses, who had to resort to using feathers of native birds. Ostriches not being known for their migratory flight over the British Isles, would mean big plumes would be few and far between.
But at the end of the day they are your toys, and if you want them go for it.
Maybe just use plumes for the command figures? PP 'officer' is barely different from the rank and file. I added a scarf using green stuff (the plumed versions were not available when I bought mine, although tbh I would probably not have bought them).
Very important to add a herald to your unit, heralds were really important historically, their role was much more than just playing their trumpet.
