Rain team featuring Electric Seed Hawlucha

Ever since I saw that Electric Seed Hawlucha was viable, I decided to throw together a team to test it out. Rain offense was one of my favorite play styles in Gen V because it let me do stupid things like using Sub + Calm Mind + Thunder Jirachi and letting Toxicroak run around getting free recovery.

Anyway, here's the team:

Pelipper:

-Scald
-Hurricane
-U-turn
-Roost
Nature: Bold
EVs: 252 HP/252 Def/4 SDef (this was the old defensive spread before the new one was come up with)
Item: Damp Rock
Ability: Drizzle

Pelipper is here to set up the rain that supports Swampert and Tapu Koko (more on them below). The main thing it did was a slow U-turn to any of my attackers. Scald is the rain-boosted STAB, while Hurricane lets Pelipper hit Grass Pokemon that would give Swampert and Tapu Koko trouble when Hawlucha is unavailable. What I like about Pelipper over Politoed is its access to reliable recovery to let it stick around longer so it can set up rain again and again.

Swampert:

-Waterfall
-Earthquake
-Ice Punch
-Superpower
Nature: Adamant
EVs: 4 HP/252 Atk/252 Spe
Item: Swampertite
Ability: Torrent

Swampert benefits from the rain that Pelipper provides thanks to Swift Swim doubling its Speed and the power boost to Waterfall. Superpower is here to lure in Ferrothorn and hit it hard.

Tapu Koko:

-Thunder
-Hidden Power (Ice)
-U-turn
-Taunt
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Magnet

Thanks to the rain Pelipper brings out, Tapu Koko's Thunder becomes 100% accurate. Once again, U-turn is for pivoting purposes. Taunt stops walls from setting up. HP Ice hits Garchomp, Zygarde, and Therian Landorus supereffectively. The Electric Terrain Koko summons is important for activating Hawlucha's Electric Seed.

Hawlucha:

-Swords Dance
-High Jump Kick
-Acrobatics
-Stone Edge
Nature: Adamant
EVs: 104 HP/252 Atk/152 Spe
Item: Electric Seed
Ability: Unburden

Hawlucha is the team's primary way of muscling past bulky Grass Pokemon. The Electric Seed is important for the Defense boost to let it take priority attacks more easily and to activate Unburden instantly while Electric Terrain is on the field.

Keldeo:

-Hydro Pump
-Secret Sword
-Scald
-Icy Wind
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Choice Specs

I was originally going to go with Kingdra in this slot, but I didn't want to make the team totally dependent on Pelipper's rain, so I went with Keldeo instead. Under rain, its Hydro Pumps and Scalds are terrifyingly strong with a Choice Specs boost. Icy Wind hits Lati@s on the switch and Secret Sword is to muscle past special walls (especially Chansey).

Ferrothorn:

-Stealth Rock
-Leech Seed
-Power Whip
-Gyro Ball
Nature: Relaxed
EVs: 252 HP/88 Def/168 SDef
Item: Leftovers
Ability: Iron Barbs

Ferrothorn sets up Stealth Rock for the team and also benefits from the rain by having its Fire weakness reduced. Alongside Tapu Koko, it helps keep opposing Water Pokemon at bay with Power Whip.

A consideration to the team is swapping out Ferrothorn for Z-Crystal Therian Landorus because it provides a stronger offensive presence. Any thoughts on this?

I wouldn't recommend replacing Ferro, because you need it for Magearna (+2 outruns Adamant Mega Swampert in rain), Tapu Lele, Zygarde, Mega Diancie, etc.

I don't see any problems with the team honestly. Maybe try Knock Off, Protect, or even Thunder Wave (in case Pelipper goes down) over Gyro Ball on Ferrothorn.

While it's not necessary, you could try to fit in hazard control somehow. SDef Excadrill over Ferrothorn or Starmie over Keldeo. However, both have disadvantages: using Exca means you lose a valuable Water resist, and using Starmie means you have to rely on Ferro as your sole defensive check for Greninja. Some weird Ice Beam / Defog / TWave or EQ (for Magearna) / Soft-Boiled Mew set could be tried over Ferro and SR on Swampert, but it's a very questionable moveset lol. Ultimately it's probably better left alone.