Thanks Anthony! That answers the question about the presence of members of Dockery's Brigade of Paroled and Exchanged Prisoners from Vicksburg and Port Hudson. According to Roll 87, Little Rock, Ark., military prison, Vol 289-291 Registers of prisoners, 1863-65, https://archive.org/stream/selectedrecordso0087unit#page/n66/mode/1up beginning on page 66 is "Little Rock Ark, Book No 1, Alphabetically arranged A to Z" for the period September 1864 through February 1865.

On Alphabetical page, there is a list of the prisoners Name, Rank, Company, Regiment, When Captured, Where Captured, When Confined, When Released, and Remarks.

In almost every letter of the Alphabet, there is a list of Prisoners captured on March 29, 1864, at Longview in Ashley County.

You are correct that the majority are from Wright's Arkansas Cavalry, the 1st Arkansas Cavalry (which I assume is Crawford's regiment), and the 2nd Arkansas Cavalry (Morgan's ???), BUT,

on almost every page there are also Prisoners listed as captured at Longview on March 29th men from the following units from Dockery's Brigade:

10th Arkansas (listed as 10th Arkansas Mounted Infantry)
11th Arkansas (listed as 11th Arkansas Mounted Infantry)
12th Arkansas Regiment,
15th Arkansas (listed as 15th Arkansas Mounted Infantry)
Carroll's 18th, (listed as 18th Arkansas Mounted Infantry)
Dockery 's 19th, (listed as 19th Arkansas Mounted Infantry)
20th Arkansas,
16th Arkansas (listed as 16th Arkansas Mounted Infantry)
Craven's 21st Arkansas
23rd Arkansas

about the only Vicksburg or Port Hudson units that I didn't see were Power's 14th Arkansas, 8th Arkansas Battalion, and 12th Arkansas Battalion.

There are also a lot of Longview related Prisoners from Woods Missouri Cavalry and the 24th Texas Cavalry.