Maybe Tom,
@tdubel, will see this and post. These are figures he sold about a week, 10 days ago, on eBay. I saw his auction and reached out to ask this very question. He said they are Stadden. I'd never seen mounted Staddens with bases like these, but apparently they were available as a custom item if you ordered from the factory. I'd never seen this many mounted 54mm Staddens in one group before, either. I thought at first glance that they were from Stadden's wargame catalog. Tom was kind enough to provide clarification.
Another possibility is that they are Russell Gammage's Rose figures. The heads are very reminiscent of his sculpts. If they are, they are highly modified, using the Prussian Death's Head Hussar body, with arms with instruments scratched and added. Rose didn't make any musicians for this particular subject. Some in the Facebook MyToySoldiersAndMe group suggested some other makers, like Derek Cross' All the Queen's Men, or Andrew Rose, but none are as close as either Stadden or Rose. Again, I think the sculpting matches Stadden best, Gammage second. The horses might come from a different maker, though. Both Stadden and Gammage produced horses with better detail to the reins and tack.
There were 2 Death's Head Hussar regiments, by the way. Their ancestral regiment was the Death's Head Hussars in Frederick the Great's army. They survived the catastrophe of the early Napoleonic wars, and in the early 1800s, the regiment was split to form two regiments in one of the expansions the Prussians carried out. Both daughter regiments inherited the tradition of the original regiment, just that the first regiment's color was red, and the second regiment's color was white. This was most obvious in the color of the kolpak on their busbies. These figures depict the first regiment.
Prost!
Brad