[US/UM] I need help with my Team

[MrGalaxyPants]

I need help with Silvally's memory and moveset and I am struggling with some moves and Items for my other pokemon. Also I will take any other advice I get into consderation. The pokemon I have are:

Silvally
Level: 72
Ability: RKS System
Held Item: Undecided
-Stats-
Hp: 259
Attack: 182
Defense: 150
Sp. Atk: 159
Sp. Def: 157
Speed: 201
-Moves-
Multi-Attack
Undecided
Undecided
Undecided

Decidueye
Level: 83
Ability: Overgrow
Held Item: Undecided
-Stats-
Hp: 236
Attack: 238
Defense: 144
Sp. Atk: 201
Sp. Def: 226
Speed: 140
-Moves-
Spirit Shackle - For STAB and cover against Ghost
Leaf Blade - For STAB
U-Turn - Cover against Dark
Smack Down - Cover against Fire, Ice, and Flying

Noivern
Level: 95
Ability: Frisk
Held Item: Wacan Berry - To cover electric types
-Stats-
Hp: 290
Attack: 172
Defense: 194
Sp. Atk: 260
Sp. Def: 171
Speed: 276
-Moves-
Dragon Pulse - For STAB and covering Dragon 
Air Slash - For STAB
Steel Wing - For covering Fairy, Ice, and Rock
Undecided

Absol
Level: 66
Ability: Pressure
Held Item: Undecided
-Stats- 
Hp: 208
Attack: 207
Defense: 91
Sp. Atk: 127
Sp. Def: 109
Speed: 110
-Moves-
Dark Pulse - For STAB
Future Sight - For covering Fighting
Iron Tail - For covering Fairy
Aerial Ace - For covering Fighting and Bug

Lucario
Level: 64
Ability: Steadfast
Held Item: Maybe Lucarionite?
-Stats- 
Hp: 184
Attack: 104
Defense: 184
Sp. Atk: 177
Sp. Def: 108
Speed: 141

Heliolisk
Don't have one yet so no level, ability, or stats
Level:?
Ability:?
Held Item: Big Root or Wide Lens
Parabolic Charge - For STAB and healing
Surf - For covering Ground and Fire
Thunder - For STAB and high damage
Charge - For stat changes and stronger electric moves

[Black Waterfall]

@MrGalaxyPants I am under the impression that this is your playthrough team. So what you are asking is how can you turn it into a competitive team? There is definitively a long road ahead, but it is nice that you have a rough idea of what you want. 

First of all, you need to decide the competitive format you would like to play. Essentially, the choice is between VGC (the official competitive format) or Smogon Rules (a well-known Pokemon community that focuses on competitive battling). But there are many different specific formats. There are lots of introductions to competitive battling on the internet. Maybe this guide can be helpful. You definitively want to check Smogon's Introduction to Competitive Pokemon too.

You should also keep in mind that optimal individual values (IVs), efforts values (EVs), and natures are mandatory in competitive battling. Breeding/genning Pokemon is always a good option.