I've scoured the records and can find nothing further on Selden. He is not recorded on the roster of either the Field and Staff of the regiment, nor any of the other Company rosters of officers.

Do you know the names and unit affiliations of his brothers who served in the Confederate army? Their records might lead to a clue.

A William Weaver served in his Company K, and I've included is records.

I would doubt he served as a spy. As to his siblings taking his name. Desertion in the CW cannot be looked on the same as we do today and it is hard to cast opinion on their reasoning.

William W. Weaver, Private, Co. K, age 20, enlisted June 9, 1861 at Fort Smith, recorded on the Jul/Aug, 1863 muster roll as under guard for disobedience of orders, subsequently recorded present through Aug. 31, 1864, paroled at Greensboro, North Carolina ca April 28, 1865

The following Weavers filed for Arkansas Confederate pensions. If any of these are kin, there might be some useful information found in their application papers. This is a list found by searching, S. Weaver

Charles H. Weaver
Isaiah Weaver
James W. Weaver
John S. Weaver
Joshua C. Weaver
Sam Weaver
Samuel Weaver
Thomas Jefferson Weaver
http://www.ark-ives.com/documenting/confed_pensions.aspx?fname=S&lname=Weaver