^ And the name 'Fusilier' passed on to Civ-standard 'Riflemen' armed with the likes of Dreyse, Minie Muskets, Trapdoor Rifles and standard breechloaders of the 1860-1880s ? And it is still considered valid name right?
And what's a preferred graphical representations (uniforms) of this unit?
1. Late 17th Century 'Malburian'
2. Mid 18th Century - Early Napoleonic Wars
3. 1810-1860 - Napoleonic Industrials
4. 1860-1880 'Civil War - Bismarc Wars - Pre - WW1)
Once you had a single weapon that was 'universal' for all the 'foot' (infantry), like the Fusil or flintlock musket, there is a linear progression for the infantry forces:
1700 - 1840: all armed with smoothbore flintlock muskets
1841 - 1889: all armed with rifled muskets or, increasingly, breechloaders
1889 - 1940: all armed with bolt-action magazine rifles using smokeless powder propellant
1940 - 1965: increasing numbers armed with semi-automatic rifles and then fully automatic sub-machine guns and assault rifles
1965 - 2020: all armed with assault rifles of various types
Variations during these periods were for 'specialized' troops: light infantry from the 1770s on sometimes used black powder muzzle-loading rifles (British 95th Rifles or 60th Regiment, some German Jägers). In the 19th century, light infantry tended to get the most advanced breechloading rifles first, as in the Prussian Army where the Jägers got the Dreyse needlegun in the early 1840s but the regular infantry didn't get it until about 10 years later.
As to graphic representation, my suggestions would be:
Fusilier: the mid-18th century armies of the even Year's War, the height of the 'Age of Reason' warfare. Almost everyone wears a black tricorn hat, colored coat with pinned back lapels, collar and cuffs in contrasting color, and lots of white or black leather straps and cartridge boxes.
Rifleman: The mid-19th century black powder riflemen were now in darker colors: lots of medium or dark blue coats, dark blue, white, or even red trousers, head gear mostly kepis with some variations like the Prussian spiked helmets or British tropical 'pith' helmet.
Magazine Rifleman: with smokeless powder propellants came very long ranges ad machine guns, so uniforms became 'modern' - dull brown, khaki, Feldgrau - to wear bright colors was suicidal. After 1914 helmets became the standard headgear.
After about 1980, almost everyone is in some kind of camouflage patterned uniform, but there is, if anything, even less uniformity: very single army and type of special forces seems to have their own peculiar camouflage pattern.