The early-mid 1860s seem like a more reasonable date for those Moscow photos. Moscow's population is listed at 750,000 for the mid-1880s and 370,000 for the mid-1860s. Housing conditions would have been very crowded in 19th century Moscow but not
that crowded.
Here are a few more pictures I have found:
Aerials of Halifax (North End), ~1920s
King Street, Saint John (looks to be around 1900)
