More to the point, with the demise of the series of Mexican Governments that led to the disastrous war with the North Americans, there was an effort to make a more nearly "people's army" in Mexico. That is, one that was no longer dressed in distinctive and pretentious Napoleonic Era uniforms, but something much more conservative and democratic.
This meant going to an all dark blue basic uniform with a simple shako, and later the same "kepi" adopted from very basic French designs. Indeed, the uniform transitioned to by the 1850's was quite similar to that adopted by the US Army as well.
Gone were the days of all crimson lancers and dazzling cuirassiers.
Well, almost. With the advent of Maximilian and the return of the French with Napoleon III, the hunger of the ruling classes for the "good old days" of distinctive, dramatic, and frankly dated, uniforms showed itself again.
But once Mexico was finally able to expel the invaders, it permanently returned to an understated, democratic vision of an army.
For some idea of the Army of the Republic of Mexico, follow this gisby.info/provost.htm . This page will show sample uniforms of all parties in the era of Maximilian, but scroll down the page to the Republican Army for reference.
25mm figures are available (surprise)at link
Good Luck!
TVAG