My great-grandfather was in the reorganized 4th Michigan, Co. I. I discovered that when I was researching the 19th Ohio. As it turned out the 4th Michigan was brigaded (Third Brigade) with the 19th Ohio under command of Brigade Commander Fred Knefler and Third Division Commander, the 19th Ohio's own Samuel Beatty.
The duty in Texas was dreadful with much loss to disease with one killed in action and 119 to disease in the 4th Michigan. I have 14 pages about their shared adventure in Dixie Odyssey. Other than an extensive masters degree thesis, I could find very little about this seemingly ignored service. Seems to me this would be a good field of research for one of the many authors on this forum.