For me, Shelly (I'm at Charlotte so can not say anything about the ones who come next) For many reasons.. limited access to good counters, the Prankster Rain Dance, Speed Boost Yanmega.. Anorith hits like a f*cking train and extremely good coverage all around .. Also Grass coverage in Giga Drain and Energy Ball if you can bring Rock types
Florinia and the first one were pretty easy (the first one was easy just because I picked Mudkip tho)
Heather's dad wasn't too bad, just Skuntank and Crobat were a bit of an annoyance
Kiki was a Simple Calm Mind Psychic Swoobat sweep, pretty much
Aya is also kind of annoying but you can get some good counters around Kiki's gym (Camerupt and Pallosand) just watch out for the Water moves on Drapion and Dragalge, and leave Toxapex for the end, just double target her other Pokémon (Muddy Water accuracy drops from Swampert/Marshtomp kinda helped for Icy Wind misses
Shade was pretty easy, Crunch/Sucker Punch Skuntank pretty much swept him
Radomus is annoying as well but Intimidate Play Rough/Crunch Intimidade Granbull (Because of the Gallade lead) + Drapion (Night Slash, Cross Poison, Fell Stinger, Bug Bite) kind of carry(my strategy was to kill the Reuniclus first turn since it's so OP in Trick Room (and the Magic Coat from the seed makes it so you can not stop it from Trick Rooming) and the SpA boost from the Seed makes it just yikes, from there it wasn't too bad,just don't let Gardevoir stack Calm Minds with other pokemon on it's side or she sweeps you away)
The Normal one was pretty easy except for the Porygon and Swellow
The Ice one (I don't remember her name 
) I broke the mirrors with EQ and wasn't too bad.
Samson can be annoying but Minimize/Cosmic Power/Stored Power /Moonblast Unaware Clefable with Weakness Policy totally bodies him(its a prize on the Circus itself, if it does not come with the HA just Ability Capsule it) . Had a lucky Quick Claw Play Rough with Granbull on the Hawlucha, baited Lucario to go for its Steel move, switched to Swampert and killed it, then bring Clef in safely, Minimize, Cosmic Power and sweep him with Moonblast and when he procked the Weakness Policy i went for the Stored Powers.. Huge Power Medicham is pretty helpful as well (you can get it in Route 2)
Charlotte was just a question of terminating the Superheated field with Surf+Blizzard (Swampert and Walrein with a Telluric Seed) send in my Thick Fat Haryiama with Damp Rock Rain Dance after the Ninetales came out and pretty much sweep her... Even went for the memes on Rotom (she sent it last) with Smack Down into Earth Power
