Rillaboom has very nice Attack and decent Health, but his Sp Def isn't that great, and neither is his Speed. The overall stat distribution makes him a bit of a slow physical bruiser. With regards to moveset, he has access to no Rock, Ice, or Electric type attacks to deal with the Flying weakness, and to cover the Bug weakness kind of forces you to into Acrobatics, meaning no hold item or a consumable to really benefit, but Earthquake or High Horsepower will cover the Ice, Fire, and Poison weaknesses nicely. Finally, once starter HAs are available, Grassy Surge is quite useful.
-> Drum Beating/Wood Hammer
-> Earthquake/High Horsepower
-> Drain Punch/Body Press/Brick Break
Scorbunny/Cinderace are a great physical scout or revenge KO. Very high Speed and Attack, and... that's kind of it. Access to U-Turn facilitates either strategy, letting you switch in a more suitable ally while still keeping the damage going. It's signature move, Pyro Ball, hits like a freight train at 120 base, with chance to burn, however accuracy of 90 leaves something to be desired. It's also very limited in it's uses, at a base PP of 5. While there is access to a fairly broad number of attack types, it really can't cover it's own weaknesses, necessitating smart play. When starter HAs are released, Libero is interesting. It plays a bit like Protean, but it happens after the attack, so you won't get STAB. But it does have decent defensive potential, if you can predict your opponent properly.
-> Pyro ball/Blaze Kick
-> U Turn
-> Gunk Shot/Zen Headbutt
-> Iron Head
Sobble/Inteleon have incredible Sp Attack and Speed, making them as a fairly cookie cutter Special Sweeper. The weakness to Grass can be handily covered by Ice Beam, however for the Electric weakness you're stuck with Mud Shot as your only option, suggesting you should probably switch out instead of trying to fight it out. Depending on where you intend to play, the signature move, Snipe Shot, is either very useful, or completely useless -- it ignores retargeting effects like Follow Me or Storm Drain, allowing you to still hit the intended target in Doubles or Triples. When starter HAs become available, Sniper is very powerful, however, with only Focus Energy and Air Slash to work with it, it leaves a bit to be desired.
-> Snipe Shot/Hydro Pump/Scald/Surf/Weather Ball in rain(?)
-> Ice Beam
-> Shadow Ball/Dark Pulse/other
-> U Turn(?)/filler