According to "Fortress Halifax: Portrait of a Garrison Town" by Mike Parker (Halifax, NS: Nimbus, 2004) "Britain completed its military withdrawal from Canada in 1905-06, a process that began during the Crimean War, accelerated in 1871 with the recall of remaining Imperial forces except those needed for the naval dockyards at Halifax and Esquimalt" (p. 215). By that time, in Halifax, the following were present: 5th Royal Garrison regiment, Royal Garrison Artillery, Royal Engineers, Army Service Corps, Royal Army Medical Corps, and Army Ordnance Department. Canada took over the forces and those who wanted to stay under Canadian service could do so, says Parker.
This same author quotes the Acadian Recorder as saying that there were 436 regments in Halifax between 1783 and 1896--quite a few to choose from.
The only other info I can glean from this source is that 1) the Royal Engineers were building and repairing gun emplacements as late as 1880, but it may only have been officers who were managing local volunteers 2) the Royal Artillery were in Halifax in 1880, pictured putting on a play 3) the 97th Regiment garrisoned in Halifax of an on from 1848n to 1880 4) it was the norm to have two regiments at a time in Halifax until 1883 5) the 101st Regiment under Sir Patrick MacDoungall were in Halifax in 1882.
