Kenneth, Kirby, and Jim,
I'm the one who called Tucker "captain" to imply he led a band of guerrillas, according to Leeper. Leeper just called him "Tucker." As Kirby implied, this Tucker may not have been military at all and not entitled to any rank.
Kenneth, as Kirby said, there were lots of Tuckers in this region, even though your Iron County Tucker could have been this very man we seek. It was not safe for guerrillas to operate very long in Iron County because of the large Union base there. The smaller Union base in Wayne County (Patterson) may not have been enough to keep determined bushwhackers out, even with Leeper there. However, without more information I am reluctant to give him more of a name. It is starting to look like he will have to remain simply "Tucker" when I write about him. I will leave the "Captain" part off.
Jim, I have my doubts that a Lafayette County man could have operated in this hilly region of SE MO against Leeper and his guerrilla trackers for as long as this Tucker apparently did. This looks like the work of a local man to me.
Well, it was worth a shot. Thanks for all the ideas and help.
Bruce