The enlistment information comes from the Compiled Military Service Record (CMSR) for these two men. These records may be procured from this site: http://history-sites.com/research/index.html

"Also, did they both enlist on the same day?"

Thomas W. and M. D. Truss enlisted on the same day (1 March 1862), same place (Ashville, AL) and by the same man (Capt. [Levi] Lloyd.)

"You said that Marcus died in camp...from the reading I've done that most probably means he died from disease...do you concur?"

I concur M. D. Truss died in camp as noted in his CMSR, the probable cause being disease