One of the best sources of information about the 8th Missouri Infantry at that time is "Serving with Honor, The Diary of Captain Ethan Allen Pinnell of the Eight Missouri Infantry (Confederate)" edited my Michael E Banasik and published by Camp Pope Bookshop (1999).

On October 18, 1862 Pinnell reports that they are camped, "Camp Hardee", one mile southwest from Pittman's Ferry, Current River, Randolph County, Arkansas. They stayed there until October 28th when they marched 30 miles to camp on Frederick Fork of Spring River. On October 29th they marched 15 miles and camped on English Creek, Fulton County, AR. On October 31st they marched 16 miles and camped on the South Fork of the Spring River, five miles southwest from Salem (AR). November 1st marched 18 miles to East Fork of Bennett's Bayou. November 2nd matched 18 miles to west bank of North Fork of the White River. November 3rd marched 15 miles to near residence of Judge (Jesse) Mooney, Marion County, 3 mile northeast from White River. November 4th marched 14 miles, camped one mile south of Yellville.

During this time Pinnell makes remarks about several men being left sick and a couple being reported as having died. On November 5th he reports sending 22 men to the hospital in Yellville.

Information about Coleman's command is not as detailed but from "Men of the Tenth Missouri Infantry" by Wayne Schnetzer (Two Trails Publishing) Coleman was ordered to leave MIssouri and report to Pocahontas, AR. Coleman refused and was dismissed (aroung August 31, 1862). At that time his command was dismounted and would become Companies C, D, F, G and I of the 10th Missouri Infantry Regiment. I suspect that Coleman's Cavalry would have been scattered from the area of Batesville, AR to the Rolla and Waynesville, MO area where they had been raiding General Curtis' supply lines so I doubt if there is any clear definition of their movement. We do know that they met the other units at Yellville around October 4th and by November 10, 1862 they had arrived at Camp Mulberry (on the Clarksville and Van Buren Road east of Fort Smith) and were organized as the 10th Missouri Infantry.

So Silas Headrick and William Louis Andrews were likely in the same vicinity in late October of 1862.

Hope this helps