Originally planned to launch this Fall, both the Fire Emblem app and the Animal Crossing app have been delayed.
Confirmation of this came from a press release after the announcement of Super Mario Run. Both apps are now expected to come out before the end of March 2017.
“After the launch of Super Mario Run in December, Nintendo plans to deliver its previously announced mobile device titles in the Animal Crossing and Fire Emblem series before the end of March, 2017.”
With the announcement of Super Mario Run, we now know four of five mobile games planned to release before March 2017: Miitomo, Super Mario Run, Fire Emblem, and Animal Crossing. DeNA and Nintendo’s fifth mobile title is currently a mystery, but thankfully it won’t be terribly long until we find out exactly what it is.