I appreciate your interest in attempting to replicate arms and uniforms of your ancestor. First, a Confederate soldier who served for any length of time wore different uniform issues at different times. Same is true for arms. That means you need to pick a point in time for your ancestor and attempt to replicate that.

It's critical to understand that Confederate soldiers wore and used uniforms, arms and equipment that were issued to them. These were supplemented by "found" items (taken from Federals or stolen from other soldiers and civilians) plus clothing provided from home. You would need to patiently research clothing and equipment issued by the quartermaster of the 26th Mississippi and the brigade QMs for this regiment. The brigade ordnance officer would be responsible for arms, ammunition and related items. Find those service files of those officers and study them.

If you have good evidence that arms and uniforms provided to Confederate NCOs actually differed from other enlisted men, I'd like to see it posted here. If there is a school of thought that suggests a "Confederate (1840) NCO saber and 1858 Remington New Army .44", IMHO that school needs new instruction. The "two-band Enfield with bayonet and no sword or sidearm" is more realistic but you still need to review ordnance officers records.

The other source of information are Confederate Inspection reports for 1864-65, available on microfilm. Brigade inspections list each type of weapon being used by each regiment. In both the Army of Tennessee and Army of Northern Virginia these usually include a mixture of the Austrian Lorenz, the US Springfield and the British Enfield. Subtypes are rarely identified.

I hope this is helpful.