Yeah, I figure this one may be almost impossible to unravel.
Here's the reference to Green, which is pretty nebulous--"Major Woodson ordered all companies, with the exception of Company A, to dismount. Captain Herring's Company fired at five pickets, who fled toward Vandeville's Farm. There the bushwackers (two companies, Purcell's and Green's, numbering 140 men) were hidden behind fences and in stables...."
With Purcell's men firing from the yard of Thomas Vandevier and retreating to their main camp in nearby woods, Woodson dismounted his command at the Auxvasse Presbyterian Church, now known as the Old Auxvasse Church, except for three dozen men of Company A, engaged the Rebels and overwhelmed them. The Feds were the 10th MSM Militia Cavalry (afterwards redesignated 3rd MSM Cavalry New). Woodson was then-Major, later Colonel, Richard G. Woodson. Herring's company was Company E, 10th/3rd MSM Cav. Purcell was Captain Young A. Purcell. Vandeville, as I have already revealed, was Thomas Vandevier, sometimes spelled Vandiver. 1876 Callaway County plats confirm Thomas Vandevier's farm adjoins the church grounds, which made me happy in that it gave me the specific site, with certainty, I've been trying to pinpoint for a decade or more.
So...I pretty much have it all, plus additional details, except for who the heck is "Green?" He came out of left field. This is the same day (October 16, 1862) as the concerted mass movement of a large part of Porter's command across the Missouri River just down the road at Portland. You may recall the Rebs hijacked the riverboat Emilie, and moved a number of men across before Krekel's 1st MSM Cav Battalion command, under Bruere, appeared on the scene.
Anyway, it all came together at this moment--Purcell et al were moving down with the rest of the Porters 1st NE Cavalry Regiment, kind of like a flood the zone Hail Mary pass at the end of a close football game, except here its 'everybody meet in the end zone at Portland landing to see who all can get out while the gettin's good flood the zone bum rush movement' (I'm thinking the captain of the Emilie may have been in on this, and have developed a bit of evidence toward that end).
Long story short, Green may have had no real connection with Purcell; it likely was just a bunch of different guys in Porter's command heading to the party and Purcell and Green came together right about the time the 10th MSM Cav Regiment crashed it on the north, and the 1st MSM Cav Battalion crashed it on the south.
I like your suggestions. Thanks for giving me something to work with. I'll take them and see if I can put either of these guys
in the vicinity of the Portland crossing chaos that was taking place.