As indicated in my earlier post, the 2nd Arkansas Consolidated was indeed a Trans Mississippi unit; and it included remnants of the 18th Arkansas

The Official Records show the transition from the 18th Arkansas to the 2nd Arkansas Consolidated in the following returns:

Official Records Vol XXXIV Part 1, p 784

Organization of the Confederate forces in Arkansas, General E. Kirby Smith commanding, April 20, 1864.

Dockery's Bgde
18th Ark
19th Ark-Williams
20th Ark
12th Ark Bn SS

Organization of the Army of the Trans-Mississippi Department, General E. Kirby Smith, C. S. Army, commanding, September 30, 1864.*

Vol XL! Part 3, p 968

Brigadier General Evander McNair- Second (Arkansas) Brigade.
1st Arkansas (consolidated), Lieutenant Colonel William W. Reynolds.
2nd Arkansas (consolidated), Colonel Thomas J. Reid, jr.
3rd Arkansas (consolidated), Colonel H. G. P. Williams.