Blastoise-Mega @ Blastoisinite  
I wanna mention something very important first; you cannot replace Aura Sphere! It is your main win condition vs Archaludon!
Blastoise can be tricky to use without the support Sinistcha, but it's doable. With 112/106 HP remaining, Water Spout has either 90/85 BP respectively, which is the same as Surf/Muddy Water.
However, it is within reason to replace Water Spout with Water Pulse. Blastoise is very much here to enable your actual win conditions (Sinistcha/Basculegion) most of the time, not to sweep with Water Spout.
Water Spout is very important to me though, because I play this team using the expectations I've built of my opponent's actions against them (basically, making the play that preserves Blastoise's HP).
And, you can convincingly have games where Sneasler + Farigiraf facilitates Blastoise entering already under TR with full HP (I almost always bring Kingambit those games).
Dark Pulse is kind of expendable if you choose to continue playing with Tyranitar, but genuinely coverage Blastoise being able to chew through teams is what wins me so many games.
Of note, do not always expect Aura Sphere to OHKO an Archaludon. If you don't see Leftovers, you should be very wary of Chople, unless you know they're a different item (like Wolfey's Scarf Archaludon).
However, the damage Aura Sphere does to Archaludon if you don't get bamboozled by a Chople Berry will be enough to put you in a winning position, should you play your cards right.

Kingambit @ Chople Berry  
I genuinely wouldn't change anything about Kingambit. I've considered replacing Kingambit with Torkoal or Aegislash, but it doesn't feel right. 
Sucker Punch makes Kingambit such a threatening checkmate piece for your endgame. It is genuinely so strong at dismantling teams that you need a strong reason not to bring it to a game.

Sneasler @ Focus Sash  
There's a secret aspect that I didn't get to talk about on my Twitter post. People don't understand that my Blastoise isn't Shell Smash, and that misdirection wins me many games before they even begin. Sneasler feeds into that even harder.
And... the funny story is that the team I posted originally had Sneasler before I switched to Tyranitar, and that's what I wanna talk about here: Adapting to the metagame.
This team, as purely offensive team, is so volatile that you can win or lose games that you have no business winning or losing, simply due to the decisions you make.
However, since the goal of the team is so simple (Trick Room, damage, win), it is incredibly flexible. Sneasler was added to the team because of the matchups I face in Champion Tier (so many Floette), not because it's objectively correct.
When I was trying to GET to Champion Tier, the multiple Charizard teams from that big tournament last weekend were booming in popularity. Especially that Zard Y Torkoal Hard TR team, I needed an answer, and Tyranitar was that answer.
Sneasler is VERY good though. It allows the team to play on an angle it can't with Tyranitar (entirely fast mode, or Mega Blastoise in the back who gets to come into Trick Room at full HP), and it addresses issues Cybertron mentioned.
Adamant Sneasler is very powerful at dealing with Floette, and usually has a coinflip chance of OHKOing a Chople Gambit with Close Combat (mine faints literally 50% of the time). It also deals with Meganium, who felt unwinnable prior.
In general, Sneasler just adds another layer to the team that Tyranitar doesn't, but I'm only rewarded for having Sneasler because I no longer see people running Venusaur + Charizard, or even face that many Charizard anymore.
The morale of the story is simply: Adapt to what you see. If you're making an informed adjustment for the metagame developing, and not changing your team out of frustration, you'll (ideally) begin seeing more success).

Sinistcha @ Leftovers  
CALM MIND SINISTCHA IS SO GOOD!! Seriously, it's changed the way the team feels for the better. I win so many games because of this thing, because nobody is prepared for how tanky or strong it is.
Not only does it give the team a backup (and arguably consistent) gameplan for Archaludon, it allows you to outplay so many scenarios where your opponent otherwise believes themselves free to Protect (similar to Life Dew fwiw).
Of note though, it allows Sinistcha to completely take advantage of some of the team's problem matchups. Water types are food for you, and Garchomp becomes much easier to wear down for either Sucker Punch or Sinsitcha to beat it.
Hilariously, one of the things this Sinistcha does best is take advantage of opposing Blastoise teams. The mirror can be annoying, but sapping their HP away makes them less likely to be a threat to Gambit (Spout DPulse Shell Smash sets).
Now, the one thing we can't decide on is an item. I have gone between Coba, Colbur, Kasib, Occa, and Sitrus ad infinitum, but I believe Leftovers stands atop them all. In a vacuum, it makes it the most likely to defeat what it needs to.
However, Kasib is amazing if you specifically struggle with making calls vs Aegislash correctly. I'm not sure it's worth, but it would help against Floette + Aegislash teams, since I generally don't bring Leftovers Cha vs them.
Finally, I am considering Hospitality on this CM Sinistcha anyway. I think Life Dew is whatever, but Hospitality can be the real deal. Heatproof has been amazing though, so I can't bring myself to, but I would likely run Occa if I did.

Farigiraf @ Sitrus Berry  
I wanna address some things regarding my Giraf: 1. The damage calculation being 15 rolls for a bit messed with my spread, but I have fixed it. 2. What I said on Twitter (due to character limit) isn't entirely accurate.
The 19/30+ special bulk always lived Light of Ruin, but 19/17 physical bulk still had what I remembered to be a 1/16 chance (6.25%) of being knocked out by Kingambit Kowtow Cleave anyway. However, with the calc fixed it became 1/8 (12.5%).
Now, EVing within a 1/16th chance is generally recommended, given you could get crit or they could have a boosting item anyway, but that's besides the point. The new 19/18/29+ has a 1/16 chance of surviving Light of Ruin and Kowtow Cleave.
In regards to Low Kick, breaking Chople and being able to threaten Gambit is too much to pass up on. I've tried, since Helping Hand should be amazing with Sneasler, and HH Aura Sphere does OHKO Gambit through Chople, but it feels clunky.
And, in regards to Twin Beam, I play against so many Sneasler in my ELO that I can't justify Psychic or Psyshock anymore. Maybe a third of my games come down to scenarios vs a full HP Sneasler in my Trick Room, I need to ease prediction.
However, I do genuinely wish I could still run Psychic. The damage is pitiful on Twin Beam, making the Venusaur matchup even harder to manage. So, if you're just looking to climb inside Master Ball, I'd recommend sticking to Psychic.
Similarly to Sinistcha, I've tried Colbur Berry on Giraf, but it really can't compare to Sitrus. This game, and this team are so complicated that I can't boil most games down to "surviving this hit". I roll with the punches, and it works.

Basculegion (M) @ Choice Scarf  
The one most important piece of advice I can give you regarding Basculegion is to recognize when Aqua Jet is becoming a win condition. Sometimes your opponent will just tank so many random hits that Aqua Jet can lock a game up for you.
Otherwise, I don't really have much else to say. It's good, really good in fact. I suppose I'd wanna mention to watch out for the rise of Protect (especially Focus Sash) on opposing Basculegion. I tend to assume they have it now, if I can.

Ditto @ Mental Herb  
I wanna briefly touch on some more nuanced parts of Pokemon in general, as well as the team, for those who have cared to read this far.
Related to the team: I desperately wish to fit a Fire type on this team. It would make so much sense with Blastoise, and I've considered Zard Y, Torkoal, Armarouge, and was even testing Bulk Up Ceruledge last night.
But, I would lose out on some things in regards to what I replace. I will never find the perfect 6, and that's okay. It's all about what's working for you in the moment, you gotta trust your gut, WITHOUT ignoring hard evidence otherwise.
I think Fake Out Blastoise is an amazing Pokemon. It functionally has 4 STABs! When the format began, all my friends expected me to jump on Shell Smash Blastoise, but I genuinely believe using Blastoise to support something is best.
What I'm saying is, if you like the idea of my team, but don't like THE team, change it! Do this with other people too! Post your ideas for others to critique and expand upon! I never thought I'd be in a spot like this, but it feels great!
Related to Pokemon:
Pokemon is HARD, Pokemon is COMPLICATED, and Pokemon is AMAZING! This video by Dr. Aaron Traylor may explain it better than anyone else ever has, and maybe ever will: https://www.youtube.com/watch?v=wrR6MquGU6A
Pokemon being hard is what I want to talk about though. You will lose games, I have lost games. Many games. Many games with this exact team, with the team Cybertron posted, with teams I genuinely loved with all my heart.
And that's okay. It's not possible to win every game, and improving at Pokemon takes a lot of goal-oriented work. Basically, it's about focusing on what your next step is. If you want to improve, don't lose sight of where you're going.
Laddering is genuinely a good example of this. You will hit strides where you skyrocket elo, and you will hit slumps where you lose dozens of points before you bring it back with a win. It's just how Pokemon is.
When you get frustrated, take a break. When something isn't working, reassess. And when you're feeling good? Capitalize! If you want to be good at this game, work smarter, and work with your community, you are stronger together.
After 12 years of playing this game, I can say the most important thing about succeeding in this game is keeping your head, and using it. Kinda obvious right? Stay calm, never stop learning, and try to have fun. It's Pokemon.
If you read all of that, thank you <3. I can't say I expect anyone to read this, but I appreciate anyone who does, and hope I've made this game I love a bit easier to understand for you.