1/2 of my answer
Mega Aerodactyl
You're going to be hearing me say this a lot, but there are way better options. Tyranitar technically has more power, and it has much more bulk and versatility. Landorus-Therian has power, defensive utility, and insane role compression. Also, Dragon Claw isn't a good coverage move, and your Mega Aerodactyl set is an offensive set that lacks STAB.
Tyranitar @ Choice Band
Ability: Sand Stream
EVs: 252 Atk / 4 Def / 252 Spe
Adamant / Jolly Nature
- Stone Edge
- Pursuit
- Crunch
- Superpower / Fire Punch
Stone Edge is great STAB that OHKOes or 2HKOes most neutral targets. STAB Pursuit either does a good chunk to a switching enemy, or removes them completely. The amount of things Tyranitar can force to switch out is simply incredible: Blacephalon, Chansey, the Mega Charizards, Ash-Greninja locked Choice locked into Dark Pulse or Spikes, (to some extent) defensive Heatran, Kyurem-Black, Mega Latias, Pelipper, non-Focus Blast Torndaus-Therian, Tapu Lele Choice locked into Psyshock or Psychic, Toxapex, Victini, Volcarona, Zapdos, Gengar, Hoopa-Unbound, Mega Latios, Mantine, and Reuniclus, and even a weakened defensive Heatran. Pursuit really starts to work only after you reach around 1350-1400 elo, though, so you can use Ice Punch or the move in the fourth slot that you didn't choose instead. Crunch is the more spammable and less prediction-reliant STAB option. Superpower allows Tyranitar to get rid of Heatran, and suits Choice Band Ttar's hit-and-run nature. Fire Punch hits Ferrothorn and Mega Scizor, OHKOing Ferro and having an overwhelmingly high chance to OHKO Mega Scizor. Fire Punch also allows it to hit Magearna and Mega Mawile super-effectively, 2HKOing both from full HP.
Tyranitar @ Lum Berry / Tyranitarite
Ability: Sand Stream
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Stone Edge
- Crunch
- Earthquake / Fire Punch
- Dragon Dance
If you want a Dragon Dance Tyranitar, you usually use its Mega Evolution because of its better bulk, higher Attacker stat, and slightly higher Speed. However, if you want to use another Mega Evolution, use Lum Berry. Lum Berry turns Ferrothorn and Clefable's Thunder Wave, Serperior's Glare, Zapdos's Discharge, Rotom-Wash and Sableye's Will-O-Wisp, Heatran's Lava Plume, Pelipper and Toxapex's Scald, and Toxic from Excadrill, Garchomp, Gliscor, Heatran, and Landorus-Therian into set-up fodder. Earthquake hits Toxapex, Magearna, Mega Mawile, Heatran, Excadrill, and opposing Tyranitar super-effectively. You can use Fire Punch instead though. Dragon Dance is obvious set up that boosts Tyranitar's Attack without locking it into one move, and that helps with its lackluster Speed.
Landorus-Therian @ Flyinium Z
Ability: Intimidate
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Earthquake
- Stealth Rock
- Fly
- Swords Dance
Earthquake is a great STAB move. Stealth Rock wears down switch-ins and limits the amount of Pokemon switching in and out. It is great at wearing down Landorus's counters, like Flying types, who are immune to Earthquake but weak to Stealth Rocks. Fly is usually a bad move, but when turned into Supersonic Skystrike via the Flyinium Z, it becomes a powerful wallbreaking tool with Stealth Rock. Zapdos has a high chance to be OHKOed by +2 Supersonic Skystrike after Stealth Rock, and Tornadus-Therian is OHKOed by unboosted Supersonic Skystrike from full HP. Swords Dance lets Landorus break past walls like the aforementioned Zapdos and Rotom-Wash.
Landorus-Therian @ Leftovers
Ability: Intimidate
EVs: 252 HP / 112 Def / 144 Spe
Impish Nature
- Earthquake
- Stealth Rock / Defog
- Toxic
- U-turn / Knock Off / Stone Edge
STAB Earthquake lets this defensive Landorus-T do a solid amount of damage (even without investment, base 145 Attack is still powerful). Stealth Rock wears down the enemy team. Defog removes hazards, keeping your team healthy. Toxic puts the enemy on a timer. Poison and Steel types don't want to switch in, since they risk getting hit by Earthquake. U-turn lets it pivot out of bad matchups. Knock Off removes Leftovers which in turn hastens the enemy's slow, painful death (wait, what? aren't all unnatural forms of death painful?). Stone Edge mainly gets rid of Volcarona trying to set up.
Landorus-Therian @ Choice Scarf
Ability: Intimidate
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Earthquake
- Stone Edge
- U-turn
- Knock Off / Superpower / Explosion
With Choice Scarf, traditional Landorus-Therian answers like Protean Greninja, Ash-Greninja (not Choice locked into Water Shuriken), Kyurem-Black, Serperior, Manaphy, Hidden Power Ice Tapu Koko, and some other crap are no more. Stone Edge gets rid of Flying types and Volcarona. U-turn is a great move on Choice Scarf, since you can predict a switch and get out of there, bringing in a check to the opposing Pokemon that just switched in. Once again, Stealth Rocks and other forms of hazards like Greninja and Ferrothorn's Spikes and Toxapex's Toxic Spikes are highly appreciated. Knock Off is decent coverage that removes items and makes switching in even harder, Superpower is Landorus-Therian's best bet against Ferrothorn, Kyurem-Black, Kartana, and Mega Gyarados, 2HKOing Ferrothorn and having a high chance to OHKO the other 3 after Stealth Rock. Explosion may seem like a strange move, however it is Landorus-T's best answer to Tapu Bulu and Rotom-Wash (the former halves the power of Earthquake and isn't weak to Lando's other moves, the latter is immune to Spikes, packs a super-effective STAB, is immune to Earthquake, and isn't weak to Stealth Rock).
Tsareena
Serperior has great sweeping potential, Ferrothorn has outstanding defensive utility, Tapu Bulu is a powerful wallbreaker that provides teammates with healing and weaknes Earthquake, Kartana is an excellent cleaner and sweeper. Tsareena has a high Attack stat but it isn't very fast. Your Tsareena set is good though.
Serperior @ Leftovers
Ability: Contrary
EVs: 56 HP / 200 SpA / 252 Spe
Timid Nature
- Leaf Storm
- Hidden Power [Fire]
- Substitute
- Leech Seed / Glare
Leaf Storm is powerful STAB that gives Serperior a Special Attack boost equivalent to that of a Nasty Plot boost thanks to Contrary. Hidden Power Fire gets rid of Jirachi, Kartana, Ferrothorn, Magearna, Magnezone, Mega Mawile, Mega Scizor, and Skarmory. Substitute allows Serperior to hide from all the status moves flying around OU, and lets you block a resisted hit like Rotom-Wash's uninvested Hydro Pump and Volt Switch, and Ferrothorn's uninvested Power Whip to set up for free. It helps that Serperior forces switches on a lot of Pokemon. Leech Seed can be used in conjunction with entry hazards to wear down Heatran, which is immune to Hidden Power Fire and is 4x resistant to Leaf Storm. Glare paralyzes the enemy.
Ferrothorn @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 156 Def / 100 SpD
Careful / Sassy Nature
- Spikes
- Stealth Rock
- Leech Seed
- Gyro Ball / Power Whip / Knock Off / Thunder Wave / Protect
Spikes is an entry hazard that is great at punishing grounded Pokemon, doing 25% at 3 layers, and Ferrothorn is the perfect Pokemon to take advantage of it; it's very bulky, has decent recovery, it resists Stealth Rock, and has many ways of chipping the enemy. Stealth Rock chips Flying types and Levitating Pokemon that are immune to Spikes. If you want, you can run one of the options in the 4th moveslot instead if you have another Stealth Rocker. Leech Seed does some chip damage and lets Ferrothorn heal. It can be cleared if the enemy switches, which essentially forces the enemy to switch and take entry hazard damage. The 4th slot is where things get very interesting. STAB Gyro Ball and a Sassy nature lets Ferrothorn punish fast Pokemon like Tapu Koko. If you;re running the Sassy nature, you should give it 0 Speed IVs to maximize Gyro Ball's power. Power Whip is STAB that covers a good amount of major offensive threats neutrally, and most importantly hits Ash-Greninja super-effectively. Since Leech Seed creates lose-lose situations that usually result in the enemy switching out and taking hazard damage in the process, Knock Off can be used to remove a Pokemon's boosting item or Leftovers, either making Ferrothorn even more frustratingly difficult to get rid of, or it makes the enemy faint sooner. Thunder Wave paralyzes stuff. Enough said. Protect allows Ferrothorn to scout a Pokemon's moveset and lets it deal with Mega Lopunny more easily, since instead of hitting High Jump Kick and losing 12% from Iron Barbs, High Jump Kick won't land and Lopunny will lose 50% of its HP from the side effect. The EV spread which I came up with myself lets Ferrothorn always survive Protean Greninja's Hidden Power Fire (without Life Orb equipped) after Stealth Rock. It will also always survive Protean Greninja's Fightinium Z Low Kick without hazards, and it will also survive Mega Lopunny's High Jump Kick 75% of the time without hazards.
Tapu Bulu @ Leftovers
Ability: Grassy Surge
EVs: 248 HP / 8 Def / 252 SpD
Careful Nature
- Swords Dance / Bulk Up
- Horn Leech
- Stone Edge / Superpower
- Synthesis
Swords Dance or Bulk Up can be used for set up. If you want to go the more offensive route, use Swords Dance and Stone Edge. If you want to play more defensively, use Bulk Up and Superpower. Horn Leech is STAB with a good base power boosted by Grassy Terrain, which that gives Tapu Bulu even more healing. Stone Edge smacks Tornadus-Therian, Zapdos, Blacephalon, Volcarona, and Victini. Superpower smites most Steel types at the cost of losing a Bulk Up boost. Synthesis is reliable recovery, however if you feel like Leftovers, Grassy Terrain, and Horn Leech are enough, you can use the move in the third slot that you didn't pick.
