You can always breed HA onto once pokebank comes out so you could always do that. I have the HA love ball vulpix if u want it though.
I don't know. I would say no because vgc will focus on the tapus and terrains and singles getting sand buffs. Mean hail is certainly more viable now but its still got faults. I think it will certainly be more used but as far as comp goes I still think it will be below rain and sand.
Posting this here as to avoid cluttering the PotW thread, but to answer your question from over there...
The PotW articles have been relevant as far as I know. I only started writing a few months ago, which was a crapshoot under VGC16 rules, but anything somewhat viable was given a write-up for VGC16. If they weren't, what was written was more directed towards Battle Spot Doubles (aka VGC15) or Smogon Doubles if they were banned on Battle Spot (like the mythicals).
The gen 7 articles will continue to have a VGC section, and the other VGC-writer and myself are already working hard for this format, especially since it appears that The Pokemon Company finally cares about the competitive side of the games