Danny and Bob
That is true Rector did make a declaration. But Van Dorn had already made the same declaration just prior to Pea Ridge for all available men to come to the service of their state.
I believe that these companies were the results of Van Dorns call because of the period of time necessary to get such things going. And I believe that probably most of these men were Arkansas Militia at the time. Again the James Yell/F.P.Yell connection and the defend Arkansas first attitude.
As for the Conscription Act, the Confederate States Government passed a nationwide Conscription law in April 1862. But most of those men did not start showing up in company formations until June. Which leads me back to these companies of the future 26th Arkansas answering Van Dorns declaration, but were not organized well enough to accompany Van Dorn to Mississippi.
"How many men were in Sulphur Springs at this time?"
There was less than a regiment of Infantry at the time of Roanes report at the end of May. The order to move those troops to Little Rock pretty well emptied the out everybody except for clerical operation at the end of May. However, by mid June (battle of St Charles) Roane was again in command of several companies of Cavalry and some infantry at Sulphur Springs/Pine Bluff. And by July Sulphur Springs had become the assembly point for Shavers Brigade (18th 24th and Crawford batt) And Garlands Texas Brigade (6th Texas, 24th and 25th Texas Cav Dis) as well as Parson 12th Texas cavalry and Carters 21st Texas Cavalry. Possibly as many as 8,000 troops at that time.