My point of using Dewgong was obviously not to have an Ice type fighter as I was debating whether even to give it an offensive Ice Type move. I like Dewgong and that's why I wanted to use it. If it's not viable, I'm going to use a water type. But it's NU, and Dewgong isn't exactly frail.. I think you underrate it. (I was going to use Luxray with Ice Fang.)
I thought you were lying when you said Typhlosion was RU, because I distinctly remember it being NU. But you're right, it was just NU last gen. And I don't want to use Torkoal. The whole reason I had Leafeon set up to delay or prevent Stealth Rock is because there are only 5 Rapid spinners on NU, of which 2 are useless and the other 3 are in every team so are very predictable. I also wanted to have a strongish Special Attacker on my team. I suppose THIS is where I could put Skuntank, rather than replacing Banette with it.
Banette was the reason I decided to make this team, and the only reason I didn't have Skuntank (one of my favorite Pokemon) was because I decided to use Luxray and Banette who had Dark and Ghost attacks. I wanted to see if I could create a team with Pokemon I liked that could make Banette not complete trash. Plus, Banette isn't used often, so I've got the element of surprise on my hand with it (unless if someone googles Smogon Banette haha)
On another note, are you really sure Marowak is going to be fine without Trick Room? It's speed is pitiful (admittedly it has strong defenses so it might not matter too much.)
I said I didn't want to use Wild Charge. Especially when it's super effective, the recoil is insane. And with Flame Orb? Luxray would be deeeead. I'll consider just replacing it with Zangoose, but I would want to teach Zangoose Ice Punch in case of friggin' Dragonair, Fraxure and that other NFE dragon. I haven't considered Zangoose before, and seeing it's Toxic Boost ability, I think it's an equal replacement.
Skuntank's Taunt is enough to keep Stealth Rock at bay.
Banette is meant to be a suicide Trick Room user, and it's not meant to last long. Its movepool is extremely shallow and it has poor defenses; the latter trait makes it ideal as a suicide Trick Room setter. Also, Banette must be paired with strong Trick Room users like Marowak (this suggestion is assuming you keep Banette):
-Shadow Claw (really, there's no need for Shadow Sneak while Trick Room is active)
EVs: 252 Atk
Item: Focus Sash
Ability: Insomina/Cursed Body
Something that can pair well with Luxray or Zangoose is Alomomola, who can restore their health with Wish. It should go over Dewgong. The only thing Dewgong is good for is Rain Dance support. It's just too weak to accomplish much, and its defensive typing sucks; this gives it reasons why it's not used often, even in NU:
EVs: 252 HP/252 Def/4 SDef
Zangoose's Facade hits Dragons hard enough already, so there's no need for Ice Punch. All it needs to use alongside Facade are three of the following: Close Combat for Rocks/Steels, Night Slash for Ghosts, Quick Attack for priority or Swords Dance to crank up its Attack to even more insane levels.
Here's what I mean:
STABed Facade: 70 (Facade's BP) x 1.5 (STAB) x 2 (Facade's power boost) = 210 BP
unSTABed supereffective Ice Punch: 75 x 2 = 150 BP
Marowak can still function without Trick Room, but it needs support from Choice Scarf users to help take down faster threats.