Hello! Before I get started, may I just say that since you're using some lower-teir Pokémon, your team may not be as strong as those who run OU & Uber teams. Here's the rundown for ya, changes are in bold~
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Whimsicott @ Leftovers
Ability: Prankster
EVs: 248 HP / 252 Def / 8 Spe
Bold Nature
- Tailwind
- Moonblast
- Taunt
- Protect / Helping Hand / Encore
This set isn't bad at all. You don't really need U-Turn though, so Encore can trap Pokes into unwanted moves, Helping Hand can give you deadly attacks, or Protect can just be a shield. Also, may I suggest, run some SpD investment for doubles in case of hard-hitting Specials that can 1-2shot you. Common Example- Heatran.
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Scizor @ Scizorite
Ability: Light Metal
EVs: 248 HP / 60 Def / 200 SpD
Impish Nature
- Knock Off / Swords Dance
- U-turn
- Bullet Punch
- Roost / Swords Dance
Nothing that I really want to change here either, however he looks fairly weak. Base damages only go so far, and U-Turn and knock off don't get technician boosted. Swords Dance would be viable, but at the cost of a coverage move or your recovery. Though this is true, U-Turn oneshots Hoopa-U and is a good pivot, and Knock Off gets big damage on bulky psychic types like Cresselia and takes off Lando-T scarfs, etc.; but KO be covered elsewhere- see below.
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Malamar @ Expert Belt
Ability: Contrary
EVs: 248 HP / 252 Atk / 8 Def
Adamant Nature
- Superpower
- Psycho Cut
- Destiny Bond / Protect
- Night Slash / Knock Off
248 in HP allows you to be as bulky as possible while still having an even Stealth Rock number. Alternatively, you can run 252 Spe to outspeed Adamant Bisharp, Adamant Mega Tyranitar, and other base 70-71 speeds without a Speed Nature. You also didn't need the investment in Defense because you have a few defensive walls already. Muscle Band isn't really as helpful as it sounds; Expert Belt let's you hit harder Super Effectively. Night Slash is for a good STAB move, as well as Knock Off if you do end up getting rid of it on Scizor. Topsy Turvy wasn't really doing anything for your team, because none of them use stat-dropping moves and aren't effected too much by Intimidate (Besides Scizor who can just U-Turn). If you do plan on using Destiny Bond, Run the Speed Investment. If not, go for Protect instead. You can scout U-Turns, stall out turns, and last a bit longer.
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Donphan @ Leftovers / Sitrus Berry
Ability: Sturdy
EVs: 252 HP / 4 Atk / 252 SpD
Impish Nature
- Stealth Rock
- Earthquake
- Rapid Spin
- Ice Shard
Ice Shard helps with Lando-T, Garchomp, and others; While not OHKOing, it does scare them out. It also gives priority, which can be useful against weaker opponents. Donphan already has a base 120 Defense, so investment wouldn't do much at all. SpD makes him bulkier all around to survive a lot more. You can also try a Sitrus Berry instead of leftovers for more instant health to prevent 2-3HKOs, but you don't have to because of Sylveon (Used to be Vaporeon, see below)'s Wish.
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Instead of Vaporeon, Try Sylveon!
Sylveon @ Leftovers
Ability: Pixilate
EVs: 204 HP / 248 Def / 56 SpD
Bold Nature
- Hyper Voice
- Wish
- Protect
- Toxic / Psyshock
Sylveon is all around better in Doubles because of Hyper Voice. I kept your EV spread, though it might be a good idea to run more HP Investment for better Wishes. Toxic is a cover move to wear down bulky opponents, or Psyshock for another damage move. You can flop it out for something else if you please.
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Typhlosion @ Choice Specs
Ability: Flash Fire
EVs: 4 HP / 252 SpA / 252 Spe
Modest Nature
- Eruption
- Earthquake
- Focus Blast
- Extrasensory
A good set. Nothing really to change here, he's decent as is.
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Hope this helped! A couple of other things I noticed:
.You have no Intimidaters, which can really hurt if not done correctly.
.Make sure you can deal with Trick Room teams. Replacing someone for A Taunter or Fake Out user might benefit you.
.Your only Status Infliction would be Toxic from the Sylveon set. Someone who can Burn or Paralyze might help you a lot more.
To cover two of these problems, you can run Sableye instead of Whimsicott, but it is your preference. Tailwind and Fairy coverage could prove more beneficial.
Sableye @ Sitrus Berry / Leftovers
Ability: Prankster
EVs: 248 HP / 252 SpD / 4 Def
Impish Nature
- Will-o-Wisp
- Taunt / Fake Out
- Foul Play / Knock Off
- Recover / Protect
Take that EV spread lightly and change it however you'd like, if you do plan on using it. Will-o-Wisp for burn and residual damage. Taunt / Fake Out for early setups and even to stop Trick Rooms. Be careful when using Taunt against Trick Rooms- most bulky TR users have a Mental Herb. Foul Play or Knock Off for a damaging move, both are self-explanatory. Recover and Protect are Defensive and correspond with whatever item you take.
Whew, I'm done typing. Good Luck!