Pearce is an interesting case, and I did not realize how much so until the past few days.
Wilson's Creek provided one of those really odd moments with 3 chiefs of independent forces on one side...and perhaps 2 on the other:
Pearce--Arkansas state forces
McCulloch--Regional CSA commander
Lyon--US forces and volunteers
Sigel--operating semi-independently/incompetently with a large contingent of the MO Germans available
Other than Pea Ridge, the closest rival to the CSA/ARK/MO arrangement ironically might be the end of Price's 1864 raid, when the Federals had the odd combination of Kansas state millitia, the Missouri state militia and Federal troops from two depts. (or was it three counting Mower's infantry?) converging.
Both instances made for one heck of an organizational mess and lost opportunities.