Sorry I don't have a better answer for the question. I have been a very serious student of Missouri Federal militia units for around a decade now, and these six month EMM units are still a mystery to me. Once I get my hands on a copy of S.O. 89 maybe things will fall into place.
Cochran has always had me a bit confounded--not only for the very unusual six month EMM unit he commanded, but also for the fact that every unit he ever led was an independent company. Shoot, even Leeper was part of a regimental chain of command, and when he didn't answer to it he found himself to have no command at all. Independent companies here and there were not that unusual, but as the militia in Missouri evolved and old units were disbanded and new ones created, the men in those independent companies generally ended up in a formal regimental chain of command. Not so with Cochran and his men. With them, it was one independent company after another after another. I never have been able to find a good bio for Cochran that might shed light what kind of pull or connections he might have had. I do know that when Price came up, it was no quarter for any of Cochran's men who came into Reb hands. I have an interesting account written by one of "Cochran's Raiders" that I'll try to dig up and transcribe for the board.