You can get an HA fennekin from a couple different methods. However, the origin requires x and y (unless you get one from trade).
-Get a fire type FS with braxien. Catch it, and it may have its HA.
-Trade with someone who has it.
-Breed your braxien with ditto or another compatible Pokemon to possibly hatch HA fennekin
I know I know, hacking is bad, but IT IS a method. Trade on the GTS for a fennekin, but a lot of people do obsurd trades (zigzagoon for lvl 100 shiny mew). The FS is the easiest method, you just need to get lucky (or have a friend with it). Breeding just allows you to get a bunch of them fast.
Hope I helped!