That was the surrender on May 4, 1865, of the Confederate Department of Alabama, Mississippi, and East Louisiana. The forces surrendered consisted mainly of the former Mobile garrison. I have acquired a large portion of the parole lists -- here is that of the officers:
https://docs.google.com/document/d/1fqI-lTg3ERXNp0KOF7zDVi7QPGeneqIHCU4Hadje76o/edit
In that list, there are twenty-five engineer officers: Col. Samuel H. Lockett, Lt. Col. Minor Meriwether, 8 captains, 6 first lieutenants, 7 second lieutenants, and 2 assistant-surgeons.