Traditionally, the marines wore scarlet red coats, the same colour as the infantry, but with different emblems and buttons and such. The officers would be wearing blue, because they would be Naval officers, unless of course they are Marine Officers in which case they would still wear Scarlet Red. There were also the Artillery which wore black, and the rangers which wore green. And, I may be wrong, but I think the engineers also wore a different colour, perhaps a different shade of blue from the Navy.
I have noticed that between the two games, Wiz and Pirate. The Marleybone soldiers seemed to have slipped backwards in time.
The Marleybone soldiers we meet in Krokotopia have uniforms modelled after a British soldier of the later Victorian period, right during the industrial revolution, which makes sense for Marleybone. These soldiers have black boots, dark trousers, short red jackets and pith helmets as seen in movies like Zulu.
But the pirate101 version of the Marleybone soldier is more similar to the uniform of a British soldier of the 1700's with white overalls, long red coats and tricornes.
I suppose it could be, because the wiz soldiers are army, whereas the pirate101 soldiers are marines, and so have different uniforms. But even then, the pirate101 Royal Marines have outdated uniforms compared to the Royal Army, since the Royal Marines of the industrial revolution switches to dark blue or grey trousers, short red jackets, and swapped out the tricorn for a bell top shako.