Well, this is going to be tricky to answer, because this is a really good team, and congrats on that. You obviously spent a lot of time on it. However, there's still SOME things that can be improved, lol. So let's get right in!
Altaria
I really don't think you need Hidden Power [Ground]. Dragon and Fire have perfect neutral coverage in NU. Torterra SHREDS both of the walls you mentioned, Probopass and Bastiodon, with its STAB Earthquake. It's also a horrible move to be locked into, as it poses no threat when not super effective, and also has a ton of immunities just begging for a free substitute / rock polish / swords dance / whatever.
So, replace it with either Dragon Pulse or Ice Beam. Dragon Pulse is a secondary STAB move, useful for when you have to dish out multiple hits in a row. However, Ice Beam has lovely coverage. In this instance, I'm going to recommend Dragon Pulse, as even though your team has no Ice type moves, your STAB dragon attacks or coverage moves hit the main targets of it hard enough. ( SDef Altaria, SDef Amoonguss, Rotom-S )
Torterra
Perfect, no suggestions. Definitely stick with Overgrow, you have no spinner.
Actually, now I think about it, your team could use some more Speed. Sawk is a great Choice Bander as well, as you know, and kills the same walls that Torterra does. Not required, but always an option.
Sawk (M) @ Choice Band
Trait: Mold Breaker
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Close Combat
- Ice Punch
- Earthquake
- Stone Edge
Pretty standard set; Close Combat is STAB and once stuff like Musharna, Misdreavus and Amoonguss have removed, you're free to spam it to victory. Ice Punch hits Flying and Grass types, and has the all important 100% accuracy. Earthquake nails Poison types. Stone Edge gets a harder hit off against Bugs, and is your strongest move against Levitating Ghost types. This guy kills off the few Steels in NU, so nothing can withstand your powerful Draco Meteors. >:3
Samurott
Also good; consider Lum Berry as it helps against various Spores, Thunder Waves and Will-O-Wisps. It's not like you'll ALWAYS be switching in on Ice moves, is it.
Luxray
I like what you've done with him here, however in reality Luxray isn't a great defensive Pokemon because of his poor typing ( including a weakness to Earthquake ) and no reliable recovery. A nice replacement would be Misdreavus, who has better defensive typing, as well as lots of nice support moves and recovery.
Misdreavus (F) @ Eviolite
Trait: Levitate
EVs: 252 HP / 224 Def / 32 Spd
Bold Nature (+Def, -Atk)
- Taunt
- Will-O-Wisp / Thunder Wave
- Shadow Ball
- Pain Split
Trachy always runs 28 speed EVs, so I always run 32 :D Eviolite and the EV spread give it very respectable bulk. Taunt is chosen over Heal Bell since you have that on Lickilicky. Will-O-Wisp is preferred to cripple most physical attackers, but Thunder Wave is always an option in case you miss the paralysis support from Luxray. Shadow Ball is STAB in case of a faster Taunt, and Pain Split is recovery ( sometimes unreliable, but it's better than nothing (cough LUXRAY ) ).
Lickilicky
Lickilicky doesn't fit in here much at all. You don't need a Wish passer, as 3 / 5 of your other Pokemon have access to reliable recovery and the other two are sweepers, lol. Anyway, your team also lacks Stealth Rock, which is essential for breaking Focus Sashes and wearing down stuff like Swellow, Braviary, Butterfree etc. So let's go with Miltank!
Miltank (F) @ Leftovers
Trait: Thick Fat
EVs: 252 HP / 252 SDef / 4 Atk
Careful Nature (+SDef, -SAtk)
- Stealth Rock
- Body Slam / Seismic Toss
- Milk Drink
- Heal Bell
Secondary switchin to Ice type attacks aimed at your wallbreakers, because let's be honest, Samurott doesn't have very good special defense and with residual damage adding up from hazards and Life Orb it won't stay around forever. I prefer Body Slam to Seismic Toss because I think hax is awesome, but that's your call. Milk Drink lets you never die, and Heal Bell cures your team of status. Really this Pokemon fills the same role as Lickilicky did, but 10x better.
Musharna
Almost perfect. However, run this EV spread: 240 HP / 252 Def / 16 Spd. It lets you outrun minimum speed Amoonguss before it puts you to sleep, and kill it with Psychic.
Okay then, I'm done. I hope my suggestions helped! :]