I use Pikalytics a lot for my ou teams, so excuse me if I make any mistake. Here we go...
According to that site, a core with greninja and landorous are good.
However, you do have many apparent weaknesses, such as a glaring weakness to any fire pokemon, which you may think you could pivot with greninja, but he dies to almost everything. Fini is basically your only option to countering those fire types, but can be ineffective if the opponent gets a burn.
Also, if you are using lando as a starter, it should have sash and u turn with a sash+ get rid of defog or rocks bc ur running rocks anyways and rocks just dont effect your team. Also for a rock setter, you probably shouldn't run bulk up. Use like hp ice or toxic for that slot
Ex set:
Landorus-Therian @ Focus Sash
Ability: Intimidate
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Stealth Rock
- Earthquake
- Explosion
- hidden power ice/toxic
again, good synergy with greninja
since ferrathorn has somewhat of the same role of lando as a suicide lead (i can tell by the sash). Why not use toxapex, who does have a fire resistance, and can do somewhat of the samethings that ferrathorn can do. It also does the role of fini, so you could get rid of fini as well
ex set:
Toxapex @ Black Sludge
Ability: Regenerator
EVs: 252 HP / 4 Def / 252 SpD
Calm Nature
- Scald
- Haze
- Recover
- Toxic
Now, I'm just presenting bold move teams, but maybe you could use a physically defensive koko with hawlucha, so that when they try to status, it goes onto the toxapex.
also, koko and luha have good synergy with the lando and the ninja
ex setS:
Tapu Koko @ Shuca Berry
Ability: Electric Surge
EVs: 32 HP / 88 Def / 172 SpA / 216 Spe
Timid Nature
- thunderbolt
- Volt Switch
- Hidden Power Ice
- Roost
Hawlucha @ Electric Seed
Ability: Unburden
EVs: 96 HP / 252 Atk / 36 SpD / 124 Spe
Adamant Nature
- Acrobatics
- Swords Dance
- High Jump Kick
- Roost
and to tie in the clefable and the scizzor type gap, use magearna, who can be ran specially or physically.
but you should go special:
Magearna @ Fairium Z
Ability: Soul-Heart
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Shift Gear
- Calm Mind
- Fleur Cannon
- Focus Blast/flash cannon
you are really good as just a beginner and good luck for the future in ou