The last shot is the guidon-bearer (another favourite, despite the rather heavy lance and flag) on the charging/running horse, which usually worked OK.
The lower shot shows the re-issue from the 1990-2000's, a rather insipid sky-blue, which I guess is the trouser base-colour, as opposed to the jacket/hat base-colour of the older issues. I don't know if Humbrol/Heller didn't get the colour thing, or where trying too hard to follow Esci and Atlantic? As Airfix used to lead the field, it would rather sum-up those years!
Note how the bottom row are all serving with the Confederacy...dirty Rebs! Strictly these are post-Civil War 'US Army' cavalry from the Indian Wars (slaughters), but we used them for ACW all the time, there was nothing else!
The artwork has been reversed at the printers, clearly someone who didn't collect Airfix, he/she got the colour transparency the wrong way round at a point of no return in the printing process...Doh!
As a figure he looks like the popular image of the awful self-publicist...who was a historical character, not a creation of Hollywood (although Hollywood's definitely contributed to the post-mortem mythology!), but as he served in both the Civil War and the later Western Expansion massacres, he works for both here. Of course - ironically - the most famous massacre of the genocide; was the one involving the good ol'boy himself!
Is it fair to think the Airfix US cavalry officer actually makes a better ACW officer? I think if you cut his brim-off and flocked his hat with some black velvet fluff he'd make a good Cossack! One day I'll try it and pop the result on this post...