Overall, the Pokemon choices are fine, as Electric Mono in SS tends to use the same 5-6 Pokemon. The sets do need improvement, however. So, here is the team rate:
Regieleki
Regieleki isn't really that good in SS Monotype. The only thing Regieleki does is improve the matchups you should already be winning. I would replace Regieleki with Raichu-Alola, with this set:
Raichu-Alola @ Life Orb
Ability: Surge Surfer
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Rising Voltage
- Psyshock
- Focus Blast
- Grass Knot / Nasty Plot
Pretty standard set. You can choose between Grass Knot or Nasty Plot if you want to make Raichu-Alola a setup sweeper. However, if you still want to use Regieleki, I suggest getting rid of Magnezone so you can have both Raichu-Alola and Regieleki. As for the Regieleki set, I would change the nature to Timid and change Electro Ball to Ancient Power, so it would look like this:
Regieleki @ Choice Specs
Ability: Transistor
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Rising Voltage
- Thunderbolt
- Volt Switch
- Ancient Power / Rapid Spin
Ancient Power is used to chip Landorus-Therian, while Rapid Spin allows for role compression for Electric-type teams.
Zeraora
Air Balloon isn't a good item for Zeraora. Instead, I would use either Choice Band or Bulk Up. Choice Band is used more often, but I'll put both sets. Choose which set you prefer, whether you want an immediate wallbreaker or a setup sweeper.
Zeraora @ Choice Band
Ability: Volt Absorb
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Plasma Fists
- Close Combat
- Knock Off
- Outrage
or
Zeraora @ Leftovers
Ability: Volt Absorb
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Bulk Up
- Plasma Fists
- Close Combat
- Knock Off
Tapu Koko
Magnet is not good item for Tapu Koko. Tapu Koko is used as a Choice Specs attacker on Electric mono teams. Here is the standard set:
Tapu Koko @ Choice Specs
Ability: Electric Surge
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Thunderbolt
- Volt Switch
- Dazzling Gleam
- Grass Knot
Grass Knot is needed to hit ground types like Seismitoad and Hippowdon.
Magnezone
Air Balloon and Magnet Rise are fine on Magnezone. However, I would change the ability to Magnet Pull so you can trap Choice Locked Excadrill. I would also recommend making the set an IronPress set, so you can be able to setup on steel types that you trap using Magnet Pull. Here is the set I would recommend:
Magnezone @ Air Balloon
Ability: Magnet Pull
EVs: 252 HP / 44 Def / 212 Spe
Bold Nature
IVs: 0 Atk
- Magnet Rise
- Iron Defense
- Body Press
- Discharge
Also:
However, if you still want to use Regieleki, I suggest getting rid of Magnezone so you can have both Raichu-Alola and Regieleki.
Remember how I said that if you're still going to use Regieleki, you should drop Magnezone to have both Raichu-Alola and Regieleki? This only applies if you are using Regieleki.
Zapdos
Defog Zapdos is fine, but Zapdos needs Heavy Duty Boots if you're using a Defog set. I would also have Zapdos use a more bulky spread. You should also have Roost if you plan on using Defog so you have recovery. Here is a set to use:
Zapdos @ Heavy-Duty Boots
Ability: Static
EVs: 248 HP / 196 Def / 64 Spe
Bold Nature
IVs: 0 Atk
- Volt Switch
- Heat Wave / Hurricane
- Defog
- Roost
Volt Switch allows you to bring in teammates, while Heat Wave is used to chip Grass- and Steel-types like Ferrothorn and Scizor. You can use Hurricane over Heat Wave as well.
For the last Pokemon on the team, we are going with....
Rotom-Wash
Rotom-Wash @ Leftovers
Ability: Levitate
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Hydro Pump
- Volt Switch
- Will-O-Wisp
- Pain Split
Rotom-Wash's defensive typing provides good utility, making it a good defensive Pokemon. Since Zapdos is using Defog, Pain Split is used as the 4th slot to provide recovery and help wear down opposing Pokemon. Here is the overall team, with two versions:
(Team Without Regieleki)
(Team With Regieleki)
Hope this helps!
