If you're going to give a Banette set that obviously is going to need to be used on a trick room team, it would help to say so in a description (I mean, you have -Speed abilities and everything), and a description would help us better understand what you expect this set to do. Moving on, Shadow Sneak isn't that great to run on Banette, especially when it has a better priority option in Sucker Punch. Shadow Claw is obviously the better option for that slot, as it provides reliable damage as well as get a STAB boost. Thunderbolt literally has no reason to be used, outside of hitting Wartortle harder; everything else is better taken care of by Shadow Claw or Sucker Punch. The best option for that slot would either be Trick Room, which would enable Banette to "outslow" things, or Sucker Punch for priority and better coverage. THe removal of Thunderbolt also means that the Special Attack EVs are not necessary, which can be better invested in HP, as it will allow Banette to survive at least one move from a not too powerful Pokemon rather than being KO'd immediately. Will-O-Wisp is a good option as it allows Banette to cripple physical attackers hat otherwise could cause Banette problems. Night Shade is another move with no viable use, as anything it would need to hit would be better taken care of by another member of Banette's team (basically anything physically bulky), as Banette can't afford to not do serious damage to something as it generally will be KO'd after it hits.
Moving onto your counters list, once again, just because something has a coverage move that is super effective does not make it a counter. Weezing is a decent counter in its own right, but not because of Shadow Ball, and Shadow Ball should not be run as it limits what Weezing can use for coverage that actually helps. Gorebyss is 2HKO'd by Banette and can OHKO in return, so is at best a check as it can't switch in. Glaceon is an OK counter, but is not seen at all in NU particularly as sits in the same speed tier as Banette and is Stealth Rock weak. Huntail has the same problem as Gorebyss of being 2HKO'd, meaning it can't switch in, and most NU Huntail sets run Crunch anyhow so no need to list it specifically, though Huntail has to watch out for being Will-O-Wisped. Torterra is bulky enough to take anything Banette throws at it, but also has to worry about getting burnt. Stoutland is a good check or counter as Intimidate lowers Banette's Attack and it OHKOs with Crunch. I don't see why you have a "unofficial additions" section at all as none of them will even be considered for the POTW and this is a solely POTW related thread, and even for those I have to say again that random super effective coverage moves =/= counters.
I like the way this set works (I used it on PU ladder as well for a while), and yes the extra status was nice
I found it interesting how many Pokemon came in on Banette (I used Focus Sash over Life Orb though, to take advantage of Destiny Bond more), as well as this set not needing Trick Room support.