My Soon-To-Be Competitive team?

[Gen3Charizard]

Hello everyone!! I am new to this fourm, And to competitive battling. I want to try a Pokemon league at a local convention soon and I have no idea what I am doing. I am really good at battling in game, but that is against AI.
If anyone can help me get a good moveset on my team I would be very appreciative. Without further ado, here's my team I have built.

As my Fighting Type
Hariyama:
Thick fat
Quarky nature
Scattersthings often
Current moveset:
Brick break
Vital throw
Sismic toss
Bellydrum

As my Ghost Type
Gengar
Cursed Body
Modest
Likes to relax
Current Moveset
Night Shade
Shadow Ball
Sucker Punch
Shadow Punch


As my Fire Type
Talonflame
Flame Body
Bashful
Capible of taking hits
Current MoveSet
Razor Wind
Acrobatics
FlameCharge


As my Water Type (Who knows no water moves...)
Toxapex
Limber
Calm
Highly curious
Current Moveset
VenoShock
Toxic Spikes
Baneful Bunker
Bite


As my Rock Type
Gigalith
Sand Stream
Serious
Good Perseverance
Current Moveset
Smack Down
Rock Slide
Stealth Rock
Stone Edge


As my Grass Type
Desidueye
Over Grow
Relaxed nature
Takes plenty of Siestas
Current Moveset
Synthesis
Leaf Blade
Spirit Shackle
Pluck


These are the rules of competing:

Rules and Regulations
• Each challenger must battle and defeat the first gym leader in order to advance to the next gym leader. If the challenger fails to win after the first attempt, further attempts may be made at the gym leader's discretion.
• The matches are to be played in the singles format.
• Pokémon are set to level 50. Any Pokémon above level 50 will be scaled down to level 50. Any Pokémon below level 50 is still legal, but will remain below the level cap of 50.
• Species clause: No two Pokémon on a team can share a Pokédex number.
• Item clause: No two Pokémon on a team can hold the same held item.
• One Mega Stone and One Z-Crystal may be used per team.

Banned Items
• Soul Dew

Banned Moves
• Double Team
• Minimize
• Fissure
• Horn Drill
• Guillotine
• Sheer Cold

Banned Pokémon
Mewtwo, Mew, Lugia, Ho-oh, Celebi, Kyogre, Groudon, Rayquaza, Jirachi, Dyoxys, Dialga, Palkia, Giratina, Phione, Manaphy, Darkrai, Sha ymin, Arceus, Victini, Reshiram, Zekrom, Kyurem, Keldeo, Meloetta, Genesect, Xerneas, Yveltal, Zygarde, Diancie, Hoopa, Volcanion





Thank you for any help you have for me. I would prefer to keep my current team due to the leveling factor. It happens on the 25th this month. Again, thank you for reading this.

 

[Gen3Charizard]

I apologize for double posting, However I must say that I have only defeated the third island in Pokémon Sun. I have not yet finished it.

 

[Nah]

They all need items, and you'll want to read up on EVs before you attempt this competitive battling league. You also really don't want to attempt it either until you beat Sun/Moon, so you have access to everything within the game.

Besides that, I'll just say that you won't want to use Talonflame. It was great in competitive last gen, but certain changes have made it not worth using anymore.

 

[PlatinumDude]

To be more specific, Talonflame is less viable than it was before because of the nerf to Gale Wings, which now only works while Talonflame is at full health.